It is used dry. I apply the baking soda with an artist's pallet knife which is very flexible. In most cases the part must be held so the powder doesn't move. Small pieces of wood can be used to fill larger gaps and then the baking soda used to fill the smaller ones left. As noted in another post don't let the tip of the bottle touch the powder. I use extenders to reach better and then can replace them if they do touch. Acetone will take it all apart if you need to. Tips that clog can be cleaned in a small jar with a lid also. This is best done in a well ventilated space as it can produce some nasty fumes.

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