Cleaning pistons is good general maintenance and makes a difference in the seal longevity and helps clear up the bores of any material that might lead to corrosion build up, but I'd just go ahead and order one of the aftermarket rebuild kits on Amazon/Ali and swap the pistons and seals out. Then you'll be well able to clean the piston pockets, ensuring less likelihood of corrosion build up. Those kits work well enough and are cost effective, so if you're going to disassemble a caliper you may as well rebuild it with fresh seals and pistons. Air compressor works...