Elec.static gun applies negative field(OK some can do either) to the powder. tribo effect is caused by friction of the POWDER rubbing against plastic, a positive charge, pull electrons from the powder. Lead doesn't accumulate charge easily. Thicker plastic container gives more insulation for the charge, it effectively bleeds off through the bowl. Glass has a high dielectric constant but nope, ain't going to do that! Remember the Leyden jar? Powder does get contaminated by lead dust and BB dust. Too much powder means less static per particle of powder. H2O likes to collect electrons, which kills static.