I think you're not testing your code properly: 
$ perl -wE '$_="\01\02"; say length; tr/\000-\007//; say length'
2
2

[download]

Nothing removed. (Update: But replaced, see Re^5: Illegal character CTRLCHAR code 27) Still you're on the right track. For deleting with tr///, you need a trailing /d: 

$ perl -wE '$_="\01\02"; say length; tr/\000-\007//d; say length'
2
0

[download]
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In reply to Re^3: Illegal character CTRLCHAR code 27 by moritz
in thread Illegal character CTRLCHAR code 27 by ultranerds

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