Another tip that might help someone with a Klippermate or someone that uses metal clamps. They give you a tiny piece of sandpaper to clean the clamps with, but it is awkward to use. I bought a sheet of fine sandpaper and cut small strips out of it. Then I glued the strips to the ends of a tongue-depressor which makes it easy to lightly sand-clean the clamps. It is a whole lot faster than using alcohol.
All you need is one scary stringjob where the clamps totally slip to see the value in keeping the clamps clean.