diff --git a/src/base64/base64.rs b/src/base64/base64.rs
index 713e48894..f4e04ad18 100644
--- a/src/base64/base64.rs
+++ b/src/base64/base64.rs
@@ -17,6 +17,7 @@ extern crate getopts;
 extern crate libc;
 #[phase(plugin, link)] extern crate log;
 
+use std::ascii::AsciiExt;
 use std::io::{println, File, stdout};
 use std::io::stdio::stdin_raw;
 
@@ -105,14 +106,13 @@ fn decode(input: &mut Reader, ignore_garbage: bool) {
         if ignore_garbage {
             to_decode.as_slice()
                 .trim_chars(|&: c: char| {
-                    let num = match c.to_ascii_opt() {
-                        Some(ascii) => ascii.as_byte(),
-                        None => return false
+                    if !c.is_ascii() {
+                        return false;
                     };
-                    !(num >= 'a' as u8 && num <= 'z' as u8 ||
-                      num >= 'A' as u8 && num <= 'Z' as u8 ||
-                      num >= '0' as u8 && num <= '9' as u8 ||
-                      num == '+' as u8 || num == '/' as u8)
+                    !(c >= 'a' && c <= 'z' ||
+                      c >= 'A' && c <= 'Z' ||
+                      c >= '0' && c <= '9' ||
+                      c == '+' || c == '/' )
                 })
         } else {
             to_decode.as_slice()
diff --git a/src/hashsum/hashsum.rs b/src/hashsum/hashsum.rs
index 944f7a249..2a00f3276 100644
--- a/src/hashsum/hashsum.rs
+++ b/src/hashsum/hashsum.rs
@@ -18,6 +18,7 @@ extern crate regex;
 extern crate crypto;
 extern crate getopts;
 
+use std::ascii::AsciiExt;
 use std::io::fs::File;
 use std::io::stdio::stdin_raw;
 use std::io::BufferedReader;
@@ -212,13 +213,13 @@ fn hashsum(algoname: &str, mut digest: Box<Digest>, files: Vec<String>, binary:
             let mut buffer = file;
             for (i, line) in buffer.lines().enumerate() {
                 let line = safe_unwrap!(line);
-                let (ck_filename, sum, binary_check): (_, Vec<Ascii>, _) = match gnu_re.captures(line.as_slice()) {
+                let (ck_filename, sum, binary_check) = match gnu_re.captures(line.as_slice()) {
                     Some(caps) => (caps.name("fileName").unwrap(),
-                                   caps.name("digest").unwrap().to_ascii().iter().map(|ch| ch.to_lowercase()).collect(),
+                                   caps.name("digest").unwrap().to_ascii_lowercase(),
                                    caps.name("binary").unwrap() == "*"),
                     None => match bsd_re.captures(line.as_slice()) {
                         Some(caps) => (caps.name("fileName").unwrap(),
-                                       caps.name("digest").unwrap().to_ascii().iter().map(|ch| ch.to_lowercase()).collect(),
+                                       caps.name("digest").unwrap().to_ascii_lowercase(),
                                        true),
                         None => {
                             bad_format += 1;
@@ -233,8 +234,8 @@ fn hashsum(algoname: &str, mut digest: Box<Digest>, files: Vec<String>, binary:
                     }
                 };
                 let mut ckf = safe_unwrap!(File::open(&Path::new(ck_filename)));
-                let real_sum: Vec<Ascii> = safe_unwrap!(digest_reader(&mut digest, &mut ckf, binary_check))
-                    .as_slice().to_ascii().iter().map(|ch| ch.to_lowercase()).collect();
+                let real_sum = safe_unwrap!(digest_reader(&mut digest, &mut ckf, binary_check))
+                    .as_slice().to_ascii_lowercase();
                 if sum.as_slice() == real_sum.as_slice() {
                     if !quiet {
                         pipe_println!("{}: OK", ck_filename);
diff --git a/src/truncate/truncate.rs b/src/truncate/truncate.rs
index cc071ebb2..b8e87a04c 100644
--- a/src/truncate/truncate.rs
+++ b/src/truncate/truncate.rs
@@ -14,6 +14,7 @@
 extern crate getopts;
 extern crate libc;
 
+use std::ascii::AsciiExt;
 use std::io::{File, Open, ReadWrite, fs};
 use std::io::fs::PathExtensions;
 
@@ -191,8 +192,8 @@ fn parse_size(size: &str) -> (u64, TruncateMode) {
         }
     };
     if size.char_at(size.len() - 1).is_alphabetic() {
-        number *= match size.char_at(size.len() - 1).to_ascii().to_uppercase().as_char() {
-            'B' => match size.char_at(size.len() - 2).to_ascii().to_uppercase().as_char() {
+        number *= match size.char_at(size.len() - 1).to_ascii_uppercase() {
+            'B' => match size.char_at(size.len() - 2).to_ascii_uppercase() {
                 'K' => 1000,
                 'M' => 1000 * 1000,
                 'G' => 1000 * 1000 * 1000,
diff --git a/src/uniq/uniq.rs b/src/uniq/uniq.rs
index 98fe7e2d1..61b19f1d7 100644
--- a/src/uniq/uniq.rs
+++ b/src/uniq/uniq.rs
@@ -69,7 +69,7 @@ impl Uniq {
             };
             let sliced = line.as_slice().slice(slice_start, slice_stop).into_string();
             if self.ignore_case {
-                sliced.into_ascii_upper()
+                sliced.into_ascii_uppercase()
             } else {
                 sliced
             }
diff --git a/src/wc/wc.rs b/src/wc/wc.rs
index 1548b30c1..0ac4e6605 100644
--- a/src/wc/wc.rs
+++ b/src/wc/wc.rs
@@ -14,6 +14,7 @@
 extern crate getopts;
 extern crate libc;
 
+use std::ascii::AsciiExt;
 use std::str::from_utf8;
 use std::io::{print, File, BufferedReader};
 use std::io::fs::PathExtensions;