I think I should change my name to "Paint Idiot" for all the dumb questions I seem to come up with. I'm using PPG Deltron 2000 paint. A friend has 3 gallons of reducer one each of DT860, DT870, DT885 that are several years old. So my first question is does reducer go bad or should I be OK to use these? I'm working in an old body shop garage with tons of dust and no AC, fans, etc. The forecast is for mid 80's with possible rain tomorrow with 60's at night. Today it is very humid. I want to try my hand at painting the inside moldings for my 51 Chevy. I did spray the car with primer but I have had another guy do the paint as I just didn't trust my lack of skills. But I'm thinking I would like to try learning. My second question is which of these reducers would be the best to use given the temps and my skill (or lack of) level? Thanks for the help.