This is how I did the fabric texture on Ramos' bag.
A few test sprays through a mesh piece, cut from a grease-splatter cover. I learn that you have to keep the mesh close to the surface, and you have to maintain the same distance and duration over the area, in order to make the spots consistent.
Geddy is mildly interested. Nah, not really. "Why aren't you playing with me?", he says.