I think the easiest solution to your problem would be to do feedings in a different tank/tub and just keep your favorite substrate.
This is what I was going to say. If you take her out and feed her in a tub with no substrate, or only a sheet of newspaper, she wont end up with a mouth full of anything - except "positively fluffy" rodent.
4.4.1 Normal BPs (Pandemonium, Sable, Typhon, Oberyn, Tortuga, Peekaboo, Naja, Kundalini, Icky)
1.0 Het Pied BPs (Argonaut)
1.0 Lesser x Butter BEL BP (Castiel)
0.1 Pueblan Milksnake (NoFeet!)
0.2 Cats (Little, Ty)
0.1 Dog (Lucy)
0.2 Rats (Jezebelle, Puddle)
1.2 Mouse (Lemur, Tunami and Tsunami) Vermont Strong.