Have had my AP 4 pots for a couple of months now and they're becoming increasingly difficult to clean..

There's a vertical line on each that seems duller that the rest of the finish and it's this that gets really black and takes some shifting..! In some places it's impossible to remove due to access (ie bolt heads/recess). The rest of the calipers just wipe clean..!

I'm concerned that the level of cleaning required to remove this is going to prematurely wear off powder coating..

FWIW, I don't use any kind of wheel cleaner, just car shampoo.

Apart from this they are AWSOME..!

 

Sorted it with some brake cleaner..! DOH..!