You could use a series of regex matches and use a new file to write the output. Something along the lines of

#!/usr/bin/perl

use warnings;
use strict;

my $csv = 'test.csv';
my $complete = 'output.csv';

open FILE, "<$csv";
chomp(my @file = <FILE>);

foreach(@file) {
    my @cleaned;
    my @array = split(",",$_);
    foreach(@array) {
        $_ =~ s/^C$/CONDENSED/g;
        $_ =~ s/^0H$/OHIO/g;
        #etc..for what you want to match
        push @cleaned, $_;
    }
    open OUTPUT, ">>$complete";
    print OUTPUT join(",",@cleaned)."\n";
    close OUTPUT;
}
[download]

If you don't want to use any additional modules