diff --git a/src/comp/syntax/parse/lexer.rs b/src/comp/syntax/parse/lexer.rs
index 42cc5400b0c3..5a8d72ce01f9 100644
--- a/src/comp/syntax/parse/lexer.rs
+++ b/src/comp/syntax/parse/lexer.rs
@@ -149,11 +149,11 @@ fn scan_exponent(rdr: reader) -> option<str> {
     let c = rdr.curr;
     let rslt = "";
     if c == 'e' || c == 'E' {
-        str::push_byte(rslt, c as u8);
+        str::push_char(rslt, c);
         rdr.bump();
         c = rdr.curr;
         if c == '-' || c == '+' {
-            str::push_byte(rslt, c as u8);
+            str::push_char(rslt, c);
             rdr.bump();
         }
         let exponent = scan_digits(rdr, 10u);
@@ -170,7 +170,7 @@ fn scan_digits(rdr: reader, radix: uint) -> str {
         if c == '_' { rdr.bump(); cont; }
         alt char::maybe_digit(c) {
           some(d) if (d as uint) < radix {
-            str::push_byte(rslt, c as u8);
+            str::push_char(rslt, c);
             rdr.bump();
           }
           _ { break; }
@@ -472,11 +472,11 @@ fn next_token_inner(rdr: reader) -> token::token {
                 let escaped = rdr.curr;
                 rdr.bump();
                 alt escaped {
-                  'n' { str::push_byte(accum_str, '\n' as u8); }
-                  'r' { str::push_byte(accum_str, '\r' as u8); }
-                  't' { str::push_byte(accum_str, '\t' as u8); }
-                  '\\' { str::push_byte(accum_str, '\\' as u8); }
-                  '"' { str::push_byte(accum_str, '"' as u8); }
+                  'n' { str::push_char(accum_str, '\n'); }
+                  'r' { str::push_char(accum_str, '\r'); }
+                  't' { str::push_char(accum_str, '\t'); }
+                  '\\' { str::push_char(accum_str, '\\'); }
+                  '"' { str::push_char(accum_str, '"'); }
                   '\n' { consume_whitespace(rdr); }
                   'x' {
                     str::push_char(accum_str, scan_numeric_escape(rdr, 2u));
diff --git a/src/comp/syntax/parse/token.rs b/src/comp/syntax/parse/token.rs
index 14f7c055743a..60949f7793cb 100644
--- a/src/comp/syntax/parse/token.rs
+++ b/src/comp/syntax/parse/token.rs
@@ -139,7 +139,7 @@ fn to_str(r: reader, t: token) -> str {
         // FIXME: escape.
         let tmp = "'";
         str::push_char(tmp, c as char);
-        str::push_byte(tmp, '\'' as u8);
+        str::push_char(tmp, '\'');
         ret tmp;
       }
       LIT_INT(i, t) {
diff --git a/src/libcore/str.rs b/src/libcore/str.rs
index 1f1f5a22ac21..5fac1b99bf9f 100644
--- a/src/libcore/str.rs
+++ b/src/libcore/str.rs
@@ -26,10 +26,6 @@ export
    pop_char,
    shift_char,
    unshift_char,
-   push_byte,
-   //push_bytes,
-   pop_byte,
-   shift_byte,
    trim_left,
    trim_right,
    trim,
@@ -137,7 +133,7 @@ fn from_byte(uu: u8) -> str {
     from_bytes([uu])
 }
 
-fn push_utf8_bytes(&s: str, ch: char) {
+fn push_utf8_bytes(&s: str, ch: char) unsafe {
     let code = ch as uint;
     let bytes =
         if code < max_one_b {
@@ -168,7 +164,7 @@ fn push_utf8_bytes(&s: str, ch: char) {
              (code >> 6u & 63u | tag_cont) as u8,
              (code & 63u | tag_cont) as u8]
         };
-    push_bytes(s, bytes);
+    unsafe::push_bytes(s, bytes);
 }
 
 /*
@@ -303,58 +299,6 @@ Prepend a char to a string
 */
 fn unshift_char(&s: str, ch: char) { s = from_char(ch) + s; }
 
-/*
-Function: push_byte
-
-Appends a byte to a string.
-
-This function is not unicode-safe.
-*/
-fn push_byte(&s: str, b: u8) { rustrt::rust_str_push(s, b); }
-
-/*
-Function: push_bytes
-
-Appends a vector of bytes to a string.
-
-This function is not unicode-safe.
-*/
-fn push_bytes(&s: str, bytes: [u8]) {
-    for byte in bytes { rustrt::rust_str_push(s, byte); }
-}
-
-/*
-Function: pop_byte
-
-Removes the last byte from a string and returns it.
-
-This function is not unicode-safe.
-FIXME: move to unsafe?
-*/
-fn pop_byte(&s: str) -> u8 unsafe {
-    let len = byte_len(s);
-    assert (len > 0u);
-    let b = s[len - 1u];
-    s = unsafe::slice_bytes(s, 0u, len - 1u);
-    ret b;
-}
-
-/*
-Function: shift_byte
-
-Removes the first byte from a string and returns it.
-
-This function is not unicode-safe.
-FIXME: move to unsafe?
-*/
-fn shift_byte(&s: str) -> u8 unsafe {
-    let len = byte_len(s);
-    assert (len > 0u);
-    let b = s[0];
-    s = unsafe::slice_bytes(s, 1u, len);
-    ret b;
-}
-
 /*
 Function: trim_left
 
@@ -592,8 +536,6 @@ fn split(ss: str, sepfn: fn(cc: char)->bool) -> [str] {
 Function: split_char
 
 Splits a string into a vector of the substrings separated by a given character
-
-FIXME: also add  splitn_char
 */
 fn split_char(ss: str, cc: char) -> [str] {
    split(ss, {|kk| kk == cc})
@@ -1409,7 +1351,11 @@ mod unsafe {
       from_bytes,
       from_byte,
       slice_bytes,
-      slice_bytes_safe_range;
+      slice_bytes_safe_range,
+      push_byte,
+      push_bytes, // note: wasn't exported
+      pop_byte,
+      shift_byte;
 
    // Function: unsafe::from_bytes
    //
@@ -1462,6 +1408,43 @@ mod unsafe {
        assert (end <= byte_len(s));
        ret slice_bytes(s, begin, end);
    }
+
+   // Function: push_byte
+   //
+   // Appends a byte to a string. (Not UTF-8 safe).
+   unsafe fn push_byte(&s: str, b: u8) {
+       rustrt::rust_str_push(s, b);
+   }
+
+   // Function: push_bytes
+   //
+   // Appends a vector of bytes to a string. (Not UTF-8 safe).
+   unsafe fn push_bytes(&s: str, bytes: [u8]) {
+       for byte in bytes { rustrt::rust_str_push(s, byte); }
+   }
+
+   // Function: pop_byte
+   //
+   // Removes the last byte from a string and returns it.  (Not UTF-8 safe).
+   unsafe fn pop_byte(&s: str) -> u8 unsafe {
+       let len = byte_len(s);
+       assert (len > 0u);
+       let b = s[len - 1u];
+       s = unsafe::slice_bytes(s, 0u, len - 1u);
+       ret b;
+   }
+
+   // Function: shift_byte
+   //
+   // Removes the first byte from a string and returns it. (Not UTF-8 safe).
+   unsafe fn shift_byte(&s: str) -> u8 unsafe {
+       let len = byte_len(s);
+       assert (len > 0u);
+       let b = s[0];
+       s = unsafe::slice_bytes(s, 1u, len);
+       ret b;
+   }
+
 }
 
 
@@ -1914,17 +1897,17 @@ mod tests {
     }
 
     #[test]
-    fn test_shift_byte() {
+    fn test_shift_byte() unsafe {
         let s = "ABC";
-        let b = shift_byte(s);
+        let b = unsafe::shift_byte(s);
         assert (s == "BC");
         assert (b == 65u8);
     }
 
     #[test]
-    fn test_pop_byte() {
+    fn test_pop_byte() unsafe {
         let s = "ABC";
-        let b = pop_byte(s);
+        let b = unsafe::pop_byte(s);
         assert (s == "AB");
         assert (b == 67u8);
     }
diff --git a/src/libstd/fs.rs b/src/libstd/fs.rs
index de4789fdd399..c367e590d397 100644
--- a/src/libstd/fs.rs
+++ b/src/libstd/fs.rs
@@ -89,14 +89,14 @@ any leading path separator on `post`, and returns the concatenation of the two
 with a single path separator between them.
 */
 
-fn connect(pre: path, post: path) -> path {
+fn connect(pre: path, post: path) -> path unsafe {
     let pre_ = pre;
     let post_ = post;
     let sep = os_fs::path_sep as u8;
     let pre_len = str::byte_len(pre);
     let post_len = str::byte_len(post);
-    if pre_len > 1u && pre[pre_len-1u] == sep { str::pop_byte(pre_); }
-    if post_len > 1u && post[0] == sep { str::shift_byte(post_); }
+    if pre_len > 1u && pre[pre_len-1u] == sep { str::unsafe::pop_byte(pre_); }
+    if post_len > 1u && post[0] == sep { str::unsafe::shift_byte(post_); }
     ret pre_ + path_sep() + post_;
 }
 
diff --git a/src/test/bench/99bob-iter.rs b/src/test/bench/99bob-iter.rs
index 02d55cf64d37..0dd66555a6bd 100644
--- a/src/test/bench/99bob-iter.rs
+++ b/src/test/bench/99bob-iter.rs
@@ -22,7 +22,7 @@ fn b8() -> str {
     ret "Go to the store and buy some more, # of beer on the wall.";
 }
 
-fn sub(t: str, n: int) -> str {
+fn sub(t: str, n: int) -> str unsafe {
     let b: str = "";
     let i: uint = 0u;
     let ns: str;
@@ -32,7 +32,8 @@ fn sub(t: str, n: int) -> str {
       _ { ns = int::to_str(n, 10u) + " bottles"; }
     }
     while i < str::byte_len(t) {
-        if t[i] == '#' as u8 { b += ns; } else { str::push_byte(b, t[i]); }
+        if t[i] == '#' as u8 { b += ns; }
+        else { str::unsafe::push_byte(b, t[i]); }
         i += 1u;
     }
     ret b;
diff --git a/src/test/bench/99bob-simple.rs b/src/test/bench/99bob-simple.rs
index 6d8a17cc9321..c54c268cb46e 100644
--- a/src/test/bench/99bob-simple.rs
+++ b/src/test/bench/99bob-simple.rs
@@ -22,7 +22,7 @@ fn b8() -> str {
     ret "Go to the store and buy some more, # of beer on the wall.";
 }
 
-fn sub(t: str, n: int) -> str {
+fn sub(t: str, n: int) -> str unsafe {
     let b: str = "";
     let i: uint = 0u;
     let ns: str;
@@ -32,7 +32,8 @@ fn sub(t: str, n: int) -> str {
       _ { ns = int::to_str(n, 10u) + " bottles"; }
     }
     while i < str::byte_len(t) {
-        if t[i] == '#' as u8 { b += ns; } else { str::push_byte(b, t[i]); }
+        if t[i] == '#' as u8 { b += ns; }
+        else { str::unsafe::push_byte(b, t[i]); }
         i += 1u;
     }
     ret b;
diff --git a/src/test/bench/shootout-fasta.rs b/src/test/bench/shootout-fasta.rs
index 7145c0fc1054..fbcc9c507b82 100644
--- a/src/test/bench/shootout-fasta.rs
+++ b/src/test/bench/shootout-fasta.rs
@@ -47,8 +47,8 @@ fn make_random_fasta(id: str, desc: str, genelist: [aminoacids], n: int) {
     let rng = @{mutable last: std::rand::mk_rng().next()};
     let op: str = "";
     uint::range(0u, n as uint) {|_i|
-        str::push_byte(op, select_random(myrandom_next(rng, 100u32),
-                                         genelist) as u8);
+        str::push_char(op, select_random(myrandom_next(rng, 100u32),
+                                         genelist));
         if str::byte_len(op) >= LINE_LENGTH() {
             log(debug, op);
             op = "";
@@ -57,12 +57,12 @@ fn make_random_fasta(id: str, desc: str, genelist: [aminoacids], n: int) {
     if str::byte_len(op) > 0u { log(debug, op); }
 }
 
-fn make_repeat_fasta(id: str, desc: str, s: str, n: int) {
+fn make_repeat_fasta(id: str, desc: str, s: str, n: int) unsafe {
     log(debug, ">" + id + " " + desc);
     let op: str = "";
     let sl: uint = str::byte_len(s);
     uint::range(0u, n as uint) {|i|
-        str::push_byte(op, s[i % sl]);
+        str::unsafe::push_byte(op, s[i % sl]);
         if str::byte_len(op) >= LINE_LENGTH() {
             log(debug, op);
             op = "";