I found a nifty use for paint brushes that I used with primer and planned on disposing of (didn't want to waste the $10 paint thinner cleaning) after they got hard. I use them with used synthetic oil from the PU and spot apply the oil, to bolts, etc.Oiled down my front differential, driver's side frame rail and a few spots on my M1102 trailer that I towed thanks to my accessory drive leak on my nifty 250.
Your method is certainly more effective at an overall lube however. (knocking on wood)