I was just concerned because in the past I've never had a mite problem with cultures. I know they were always there, but they got a good foothold on 2 of my current cultures (which are now RIP in the trash after I gave my frogs a healthy feeding lol). I have mite spray for birds since I used to have parrots (before the g/f moved out and took them), so I'll be doing the paper towel thingy.
BTW, the cultures infested were just over the 30 day rule by one week. I'm sure you know how hard it can be to throw away cultures that are still producing

And now I'm low on flies so I'll be going to the local pet store for a new batch I can feed while my others catch up. Thanks for the info.