awesome, I was struggling to figure out where tracers went, I’ll try the light trick.
I did try using flux, I tried cleaning it with a toothbrush dipped in isopropyl alcohol, but I’ll try water and bud tomorrow.
I think I’m using decent solder, I bought it from my local electronics store. It has no discernible branding but does contain a mixture which includes flux. My soldering iron is a fairly expensive one and has treated me well, but I don’t think I take good care of the tip.
I’ll try a sand as well tomorrow. Thanks for all the advice and encouragement :D