You should wash your fabric first, I don;t think it matters with fleece but I don't LOL

If you have PUL I was use that but if you want to make a few with out it just use 2 layers of your SL fleece but the PUL would be better.
The other Fleece you can use is the Malden Mills Fleece but thats one you have to get online. I have some here that I am making covers from.
Wish I had the car to go to SL, I have a layby of 9 metres of cotton rich I want to get out!