you also don't escape characters in a character class. your regex (once g is added for global) will strip back slash characters, as well as braces.

No, it doesn't. There's no need to escape the parens, but it certainly doesn't do any harm:

$_ = 'foo\bar(baz)'; print "Before: '$_'; ";
s/[\(\)]//g;         print "After: '$_'\n";
__END__
Before: 'foo\bar(baz)'; After: 'foo\barbaz'
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No backslashes are removed.