First take everything apart, everything, even the posts & pop bumpers & then really clean it good several times.
FYI: The leafs at the sling shots will bend & destroy the sponge so take those out too, don't be lazy.
The more of the stuff you use the more it splatters so dont use too much & work it in before hitting high speeds.
Also you can use masking tape on certain areas too, he includes a dvd..........perhaps I could split it up into parts & post it on youtube but its really straight forward.