[mikethedruid]

Old trick for soldering to just about any old terminal. also works for helping ancient solder melt for removal from terminals. Take some rosin, cheap violin rosin is fine, crush it up with a hammer, and dissolve it in 91% isopropyl alcohol. Using a little artists paint brush, apply it to the old solder, and give it a few minutes to dry. It acts like new rosin flux and makes the old solder flow like new. This makes it much easier to solder new things to the old terminal, or to use solder wick and / or a solder sucker to remove it. You can also apply it to solder wick to make it absorb the solder better. I always keep a little pimento jar with this mixture on my bench.