Every bass I’ve ever got preowned or in a trade usually has disgusting screws. Rust and DNA gunk etc.
I usually remove the screws. Soak in either Coke/Vinegar for a few hours, I then remove them, dry them off and use fine grit wet & dry paper over the heads, (not the threads) to remove any remaining rust until the head of the screw is clean. I then soak the screws in oil, usually a small amount of WD40 in a cup to neutralise the vinegar and stop any further rusting.
I will usually do this on all screws when I get a preowned bass, it’s especially important to keep screws clean, (bridge screws too!) because nothing annoys me more than doing a trade for a perfectly adjustable bass and getting a bass home mid setup to then realise I’m working on a bridge I can’t adjust due to seized screws and neglect or pickups I can’t lower/raise due to rusty/stripped screwheads.
I do not understand how & why bass players don’t look after their instruments and let stuff get that dirty & mank.
Obviously if the screws are stripped just remove and replace.
Look after your damn Instruments people!!
Oh and if you’re doing a trade:
1. Please clean your disgusting gunk/sweat/bodily fluids off the instrument before the trade, handing over a dusty, dirty bass shows you really have no regard for your belongings, cleaning an instrument pre trade is appreciated.
2. Disclose any dysfunctional/non working part so you’re not screwing someone over and they realise what they are getting/dealing with.
Tech & Trade addict rant over.