Thread: What solvent?

Hi all. Have had my rifle out for target practice a few times now. Had groups as small as .414". Yesterday it was out to about 2". I'm sure it's because my scope has come loose. I cleaned all the threads with 100% acetone from the pharmacy, and cotton buds, but may have missed some. What spray type oil remover do you guys use to clean up for scope-mounting? I'm gonna re-do it so want it right this time.
Cheers,
Ken