Pro using sand blasting and/or stronger chemicals.Also, another reason for this post is to show some people not familiar with striping parts, just what they should look like when done. Everyone has a different Idea of what is acceptable for prepping. Really consider if your up to the task, it's not hard, but to do it right it is time consuming, and labor intensive, however the end product in my opinion is completely worth the effort. Thank's for everyone's input, and a new respect for all you people that Polish all your parts to a mirror finish!
As for what acceptable for cleaning...
Powder could be layed on top of paint...
And a lot of people do that. I won`t...
How many chromed parts with peeling chrome you`ve seen ...
Same cause... bad surface prep.