CC use a lead-free solder, not sure if it has silver in it or not, but some ppl do have trouble melting the solder, i took an 80w iron to it & it came right off. I dont plan to use lead-free solder though, it takes much much longer to melt & is harder to work with generally compared to 60/40 rosin core.

I plan to remove all battery & motor wires, remove as much old solder from the tabs as possible, then use 60/40 or deans racing solder for the new wires...

After i finish the new wires, ill post pics of the esc & also how it was soldered to the board...