in reply to
I agree with dws,Juerd and grep, if you are writting code that is Taint-safe, then the <cod>-T</code> is just to keep you in check. I understand from your reply to dws that you are looking for things other monks have used when working with Tainted data, and i just wanted to say that i am a huge believer in the list versions of system() and exec(), and even feel a need to shamelessly promote this node about the diffrence.
Other than that, if you know your data, you will know your un-taint-o-rator. If you are using things like $bad_data =~ m/^(.*)$/; $bad_data=$1, then you have missed what tainting is about. I shy away from catch-all un-tainting, but, if you are looking for common idioms, i only usually use things like \d+ and such, though, i don't do much CGI, so i don't have the largest frame of reference :/.
just my €0.02
from the frivolous to the serious