Those 3M bristle discs are awesome but they have got ridiculously expensive. .....waiting for some china knock offs.
I used walnut shell for reloading media to clean my brassUsed to clean a lot of delicate stuff with walnut shell blasting but never tried it on pistons. I bet it works well.
I’m pretty sure simple green is safe to soak in but some of the purple power and other type cleaners will eat aluminum if left too long.For the cheap full strength simple green and a simple scotch Brite pad after overnight soaking will get off 95% of it
That stuff F's up your hands too at full strength. Easy-Off in 3 minute treatments.I’m pretty sure simple green is safe to soak in but some of the purple power and other type cleaners will eat aluminum if left too long.