Duct Cleaning / Skipper Balls (Barbed) / Skipper Ball Care & Maintenance

Skipper Ball Care & Maintenance: 

Dip skipper ball in mineral oil (varsol or paint thinner) and give them a blast of air from a blowgun which cleans the liquid and the dust out of them.
Do this several times to get them really clean.

DO NOT use any solvent that contains oil.
DO NOT lubricate with oil as the film will only attract and hold on to the dirt, where as dry fittings stay cleaner longer.