01bluecls said it correctly. When I do my customers showcars I don't use polish, because they don't see rain, or salt. Hell they only get washed at the most twice a year.
I use sonus clay, sonus paint cleaner, Klasse AIO, SGx3 and P21S. I have a customer that has 4 Camaros and he has me put 8 coats of SG on his '68 Orange with black racing stipes till the first show. Then two days before the show I put a coat of P21S and then the day before I put another coat.
clay, paint clean, aio, sg, and P21s this every 6 months and your fine. SFX-3 polish after winter season like I do just to remove some damage spots.
The thing you have to do is wash it right. Yes I said wash it right. two buckets, one with soap and one to rinse mitt. Use chennille mitt or microfiber and have two of them. I really like Sonus and P21S shampoo. Dry it with lamb leather or a sonus drying towel. Not your Walt Disney sweatshirt. That's how you get swirls.
Only use MF , no rags!.
What ever you do avoid a cutting polish. I use a non abrasive polish like Sonus SFX-3 that brings back that shine after a horrible snow-salt season. Klasse All in One is probably all you will need though. It does it all; cleans, removes swirls & oxidation, and protects.
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