Usually a bit of new solder and wipe on heatup and it’s good to go.
Weller tip activator works wonders when the iron has too much oxidation or impurities to clean normally. This is basically an agressive fllux solder. Stick the hot soldering iron in it, take it out and leave it bubbling untill it’s finished bubbling completely. Wipe and it’s now silver tipped, if not just repeat or repeat to increase thickness of the plating.
I use mg chemicals SAC305 lead free solder, I’ll dig out the precise product tomorrow. I know people find lead free more difficult but if you’re cleaning the solder points heating up the metal of the parts and then wipe adter with a qtip and iso, the results are pretty good.
I do know why people love the pb 70/30 but I’m used to this pb free solder now.
Edit:
I'd advise against any bismuth (Bi) blends due to the fragility of the solder joint given foot pedals are knocked around. Here's the all the stuff I use:
MG Chemicals #4900-454G SAC305 Sn96.2Ag2.8Cu0.4 (96.2/2.8/0.4) 21 gauge wire
MG Chemicals #837P Flux pen (it has a fibreglass tip for scrubbing clean too. Then heat the solder point and the flux cleans.
Chip Quik TS3915SNL Solder paste
Sn96.5/Ag3.0/Cu0.5 T4 for SMT/Small pad THT
Weller Tip Activator - works fine for both leaded and lead-free and I normally do a couple of dunks.
Only reason I use the silver blended older is to prevent any silver (Ag) corrosion for any wiring if it has silver in it. Normal solder will attempt to absorb the silver from wire over time. The MG solder is decent but needs the parts hot to properly solder and takes a higher temperature and there is a little learning curve for lead free solder. The ChipQuik paste is really nice, works well for soldering SMT with a normal iron.
For desoldering - braid and a a draper metal solder sucker.
Lastly the finished joints don't get left uncleaned, although water works technically, 99.9% isopropyl alcohol works better with a qtip to rub, leaving the joints sparkly and the boards clean.
There is life after lead..