This is how i used them :
Fill with 20 drops
Leave for 15mins
Fill with 10 drops
Leave for 15mins
Fill until you see it welling up on the top (no more will soak in)
Leave for 15mins
Gently blow through the cart (from the top) with paper towel at the battery end to clear any fluid from the middle. Connect battery/tank/fill it up and vape, takes a few good hits to get it going, and has a bit of a "break in" period. At 1st, i threw out lots of Carts thinking they were duff, when in actual fact i wasnt filling them well enough, or too much and flooding them

Hope that helps!