Hey,
Well, there is always going to be a problem with using anything, other than newspaper, as anything but, can also stick to the food item, particularly when wet from either the bloods saliva or water from soaking to thaw for feeding. So my choice is always going to be bar none, newspaper. However, below is a solution if you choose to use other substrates. Place some clean newspaper under the snake while feeding. When they strike and are constricting I find it easy to lift the snake up with the food still in its mouth, and place some newspaper underneath it; simple.
-Angel

-----
In life you can fall many times, but you're only a failure, if you don't try to get back up!
Evil Canevil