It's safe but IPA is not the right cleaner for the job. Which Kester flux are you using? 186? One thing I do is if I need extra flux, I put just a drop on the lead of the part. Then I don't have to clean. I have capacitors here that for whatever reason always prove challenging to solder, so I give each one a very, very light coating of 186. It's exactly right to get a perfect joint every time. I had a nice, long chit chat with a chemist over at Kester, and this was one of the tricks he suggested.
Anyhow, you're likely just making things worse by disturbing the flux and then smearing it all around. When I have to clean, I use Chemtronics Flux Off for Rosin, and then I follow it up with a cheaper alcohol spray from TechniTool. That actually gets the boards clean. IPA is lousy for cleaning off flux.
Anyhow, the only thing I generally worry about is pots and switches, but it looks like your particular pot is designed for it so it's fine.