I've got a few PK brakes and they work unbelievably well. Been shooting quite often with the braked rifles and like to keep the brakes clean.
While cleaning the rifle bore with Wipe-Out I decided to give it a try on the brake too. I laid the brake on a clean rag and sprayed the foam into it. Almost immediately light blue foam started to expand out of the ports. I was surprised because I always assumed that only carbon deposits collected in the brake which is why I usually use a carbon remover in them. The blue foam would indicate that copper was present in some form or another.
wouldn`t it be the same as shooting lead bullets the hot gasses erode a little bit of the copper bullet and end up getting deposited on the brake as the gasses are exoanding and changeing directions.