I can only tell you what I had to do on one of my old Hondas front brake callipers.One side front had a sticky piston.It looked ok but under a magnifying glass there was some slight corrosion that with my normal glasses I didn't see.I polished the piston with some Autosol Metal polish and that cured it and cleaned off with carb/brake cleaner.
I use ACF50 on the seals and piston when they are in and have had no problems since.I did my SVs the same way when I got the bike last year both front and back.
Although the Rear pins cleaned up OK they were a little pitted and one of the spring retainers was shoddy so replaced them with this kit,
https://www.ebay.co.uk/itm/AFTERMARK...:rk:3:razz:f:0
£4.95
The springs in this kit were slightly different to the ones that came off but still work and are actually easier to fit/work with.
HTH