Weeksy2,
pretty much agree with all that 'twpd' says apart from the scotch brite part. The optimum method of cleaning the surface of the pistons is clean fluid , a lint free cloth and plenty of elbow grease. Scotchbrite, however gentle it is used, is still a fairly abrasive material, there are other textiles that are similar in look and I suggest one that is suited to Teflon pans, for example, that may be used as a last resort, but in all honesty fluid, cloth and a brisk rubbing action (orch!!!) should suffice.
I cannot overstate the importance of replacing the pistons in their original bore.
Resistance to piston replacement should be firm but not sticky. Good luck
