I'm not sure I understand the question completely, but if you're *positive* something like $self->{Filename} is okay, try: my $file = ($self->{Filename} =~ /^(.*)$/; Presumably, one could untaint an object with similar code:

foreach (keys %$self) {
    $self->{$_} = ($self->{$_} =~ /^(.*)$/);
}
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The standard disclaimer this time states that doing it that way really isn't all that secure (a hash slice would be better) and that this technique will only work on blessed hashes (other objects will go BOOM).