Over the years I've collected quite a number of filters. So many Skys and UVs have arrived over the years, and I don't even use them! Secondhand lenses have come with them, cameras have come with them, family and friends have donated boxes of old photo gear with filters in with the gems and junk. Some I've actually bought myself. The Cokin multi image filter I used for his shot, for example, I've had stored away for 30 years, No idea where the blue 80B filter I'm holding came from. I have so many I'm sending them to the 'bay to raise a little cash for something more useful and maybe a little bit special... not telling you what in case demand drives prices up.