I've sold/given good used cams away for ages...hyd,solid and roller. I also have no problem with putting a used cam in my motors as long as it's inspected carefully.

I have a number of cams on the shelf that only have a few hours run time. Why would I throw them out?

I've wiped one used cam over the years and that was my fault. It was in the middle of the winter(blizzard of '77/78) because I couldn't stand the silence anymore. Racer Brown STX33 Hemi in an unheated garage(5 degrees).