i had luck with taking a clean tub put fresh shaving in there have it all set up and du,pe hem in at same time. my fiance uses the vanilla when she makes new colonies. i also take the babies when young and mix the 3 takes(back then) and just spilt the pups up into the anks so the genes kept getting mixd up lol. i wish i could trade my rats off for asf lol. cause the smell so much better with asf.