How is the sponge method of getting color on buttercream frosting done? And, how do you get the frosting color think enough to do it? Iam trying to do a Tow Mater cake for my grandson and I need to get the light blue and green on it somehow. I have heard of airbrushing but I don't have a airbrush.

Thanks
Lavina

Welcome to CC! I think if your cake already has crusted buttercream, you can thin a little gel color and just pat on gently with your sponge or whatever you want to use. You wouldn't want it to get "wet", but if the color is put on gently and a little at a time, it should be great.

They also have spray cans of different colors near the icing in the store. That is kind of the same as airbrushing.