leaving only [a-zA-Z0-9]

TriggerDunpoe has asked for the wisdom of the Perl Monks concerning the following question:

I have

$a = "dfowusgfiwu42394353****hsdfsd";
print "$a\n";
$a =~ s/!([a-zA-Z0-9])//g;
print "$a\n";
[download]

what's not right? it doesn't do anything to the string... and I know it looks useless, but it's a test for something else. what I want is to delete any and all characters from a string that don't fit into [a-zA-Z0-9]... unless things like "$(@$&%*" are in there...

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