What kind of moth balls will kill roaches in my electronics?

there are two types of moth balls, one only repels the other repels and can kill if the container is air tight... the one with the killing aspect is paradichlorabenzine (cousin to DDT). Don't think I would use them though, as you mentioned they might damage plastic...definitely do not want to use boric acid, the low ph (acidic) nature of the powder is very corrosive to metals ...go with a roach bait that comes in a large syringe, easy to use and very effective