Transmission/ cast aluminum paint prep

[Shreddinlettuce]

What is the best way to prep transmissions, valve covers, etc for paint. Planning to use engine specific spray cans. Normally I would just use acetone on a rag, but do I need to sand/ scuff or anything so I don’t peel like a Scottish bloke in Florida?

Looking for long term experience.

 

[Bebop]

media blast it.