I have a lot of these stamp that were used as postage to send material to me. These stamps seem stickier than most USA stamps. One came off after soaking but just the picture leaving the backing behind. I read that 100,000.000 were printed in 2013. I like this stamp as I like Bobcats and other wildcats.
1. Is there any mild dish detergent that I could add to the water?
2. Were there any other wildcat stamps released with these?
I had no problem soaking my 2013 Bobcat (Scott#4802) off paper. Do you have scans or images?
Maybe you could use a dish detergent, but probably some else could answer that better. I have never used anything other than water on water activated gum stamps.
There a couple variants of the bobcats in the self-adhesive format dated 2012 and 2015, Scott#4672 and 4672a. The Florida Panther (Puma concolor coryi) stamps from 2007 could be consider another wildcat from the animal "series."