If you are not using filters to view the planets and moon you are missing at least 20% of the detail, maybe more. A whole set is about the cost of a plossl, and the difference in viewing can be startling. You never know which color will do the trick on Saturn or Jupiter, so I have a complete set.I think two of these are actually not Celestron because they don't make that shade.
These filters are obviously like new, it's hard to abuse a filter, but mine do get used. I've been observing since the 70's and filters are as essential to proper viewing as any other piece of equipment in the box.
I would like to sell the set as a set. If not, I'll break them up later, but the price shouldn't hold anyone back.
#8, #11, #12, #15, #21, #23A, #25, #38A, #58, #56, #58, #80A, #82A