[Healeys] BJ8 brake caliper question

[Tom Felts]

Had my right caliper pistons seize today causing one HOT set of brake pads and roter.  Pulled them and removed pistons----very dirty as I suspected.  The piston cavities need a good cleaning.

What do you use to make sure this surface is clean and shiny before you replace the new pistons?  Don't want to sand blast---tried a real fine steel wool, but can't get it as clean as I want.

Thanks
tom