I just purchased these and need to know when once 'opened' how long is one of the boards sticky? Forever, or do they dry up and get hard after a time?

My longevity experience with these is contrary to all the other answers to this question. I got a package of these in late June 2021, and they worked great, but today, Aug. 7, 2021. I replaced them all because they were no longer sticky enough to stop bugs. Most of them were placed in window sills and received sun and some breezes. They weren't covered with dust of debris, and still felt sticky to my touch (though not all), but I saw bugs crawling over them.

The release paper won't peel off the trap. Is there some way to peel it off?

To remove the release paper, grab it at the corner and peel the paper along the trap, rather than pulling it up and away. This will make for an easier experience removing the paper. Please let us know if you have any further questions. Thank you for choosing Catchmaster!

What is the size of the sticky area on each trap?

The " is equal to an inch (imperial writing) check your U.S. Ruler length and yes that is a size, 6" inches by 8" inches is a good size for mice, I will staple or duct tape a few together for a RAT size all together and hope the sticky stuff is tough enough.

will it catch large lizards?

I have used a different brand of sticky traps in my garage to catch scorpions. I check them every day and have caught very small lizards. You can use a qtip and cooking oil to release them from the glue. I've done it several times and other than losing their tail, they scurry away as soon as the oil gets them unstuck.