Hi all,
I'm currently trying to clean 8 sealed potentiometers (they're the "ModPot" type, square pots with plastic casing).
I've seen several suggestions in various places online, suggesting using a hot soldering iron to burn a hole through the plastic pot casing and then squirting anything from wd-40(?) to various other cleaners, combined with various oils.
Is there any one procedure/cleaner that is most recommended?

Thanks

If the potentiometer is sealed, it shouldn't have any residue, debris, or oxidization on the resistive element or wiper. If too much power went through the part it might have charred the element and a replacement is in order. Sometimes a DC shift can occur with the adjustment of a control and this can result in a brushing sort of sound which might lead you to believe the control was dirty.

Sometimes just repeatedly operating the control will help with dirty contacts. A tiny bit of isopropyl alcohol can help clear residue/debris from unsealed parts, combined with repeated operation to help clear the contact surfaces.

A www search for contact cleaners and preservers might reveal specialty products/advice.

Thank you! I will probably look into replacing these, as they are quite scratchy (they are probably 20 years old).