Polyfill here too under the pan but for some cat sets we use a shingle on the pan.
We have an issue with wind blowing sets clear and anything lightweight just blows away.
We use a lot of wax dirt too.

X2 on the wind!

For 40 years now , 95% of the time I use absolutely nothing. Think about it, a properly adjusted trap has a minute amount of pan movement before firing. A small amount of dirt will get under your pan but again, a properly adjusted pan fires with little movement. Sifted dirt does not flow and level out evenly under a pan. Sifted dirt will typically only be on the outer edges of your pan and is not compressed. The sifted dirt is loose enough that it will not prevent your pan from dropping the slight distance it needs to fire. There are exceptions. Extremely dry, free flowing sugar sand and days on end of rainy conditions. During these times I use a dark colored fiberfill I purchase from Pine Hollow Trapping Supplies. I like the dark color as it blends in, unlike the white polyfill I used to use . During the described conditions, rain and blowing sand can expose your pan, which in turn leaves your underall material very noticable if it is white. In the past I have used well aired out fiberglass insulation. The downfall with it is it will lose its fluff when wet and can be quite noticeable if exposed. Hot water heater wrap, with the white plastic outer protection, worked extremely well when I could find the old style insulation, that didn't compress when wet. I used a template to draw the dimension I needed the underall to be on the white plastic portion, which I always cut smaller than the pan itself. I would cut out a good supply of them, toss them in a clean cage trap, and air them out under a protected awning until ready for use. The white plastic portion often adhered to the bottom of the pan and remained there even after a catch. Admittedly they were time consuming, expensive and when they switched the insulation material, it was time to find a better solution. Using no pan cover or underal was the the best solution. Just be certain you have properly adjusted traps, a level pan, no pan creep and proper pan tension. I understand many trappers have situations where this technique is just not feasible for their conditions, but give it a try, I am willing to bet you will be pleasantly surprised.

Good stiff wire screen is my preferred but can be hard to find, if in sandy country you can dip your wire screen in wax to seal it completely, but most of the times I use wax paper and I double it over, to me it seems to help hold the integrity of the wax paper more being doubled.

What about the Latex covers any thoughts

I use the rubber foam underalls and it’s worked well. Very seldom do we get a hard enough freeze for it to be a problem. This year I’m going to give the screen pan covers a honest try. I like the idea of the extra kill area and I’ve learned a few things about getting them to lay flat and I happen to have a huge roll I’ve had for years so why not.

I have tried lots of things. Black landscape cover I had problems with mice and voles, wax paper was not strong enough, I do use peat moss some. I finally went with poly fill under the pan. I do mine different than most people though. I buy quilt batting, it comes about 3 feet wide, but a yard of it, cut into squares. I lay it out and sharpie lines out then cut. Squares 2.5x 2.5 work for most traps, 1.5’s thru 650 Dukes. I have used these for years , some you can re-use some get destroyed. They are cheap and easy $3.00 for a couple hundred.

wws