So recently I found an old extraction that I had going on but never finished. If I recall correctly, I already did the acid stage and added salt.

I read somewhere on here (I think) that leaving it in the acid-salted stage for too long can cause other stuff to dissolve in the solution, resulting in lower/less pure yields.

Have any of you had experience with this? Should I keep going with this extraction when I have time?

If that's all you did I would just keep going, you can always clean up any impurities once you've got the goods. No point letting it go to waste, the spice is precious!