Question on clearing metal bowl of any resin and THC

[destapadore420]

Alright, I'll break the story down,
SWIM just recently got a job where SWIM is drug tested and SWIM has been forced to quit the ganja to resort to legal herbs, and it's the legit shit and SWIM is sure everyone knows the exact website where SWIM gets SWIM's alternative.

So SWIM just got my old metal bowl which was borrowed and brought back to SWIM recently so SWIM can have a piece to smoke my legal stash but forgot that it was used several times for pot. SWIM cleaned it with alcohol and salt and got it at least 99% clean of any resin. But one thing that is a concern is after being cleaned completely until there was no color brown on the whole piece, is there still a chance of THC residue left in the bowl that can't be cleaned of? I'm only concerned since I have a drug test in a week and I hope I'm not catching anything left behind that would contain the ingredient.

Should I play it safe with a new metal bowl or It's all good since I cleaned my old piece so well?