I have the same issues with these old records I am cleaning using the SpinClean record washer. Most show a lot of improvement in amount of noise, but there are certain records that continue to pop and crackle. I clean them a second time and not much improvement. I was chalking it up to excessive grove wear — I know that the equipment they were played on decades ago was not very good; neither was the care and cleaning (some were my teen party records). I hadn’t thought about static electricity. I will need to look into that.
On another thread, I asked for advice for reducing the warp in one record that I have. I think it was affected by heat somehow. My idea was to use a clothes iron to heat the record and press it flat. I laid the record on a paper record sleeve on a flat surface, then placed a microfiber towel over the record and then applied the iron (no steam). I went slowly and started out with low heat. The warp decreased but not enough to play it. So, I gradually upped the heat and it was still hard to get the record flat — If anything, it warped more on other parts of the record. I think it would take a special device that could apply heat and pressure equally over the entire record surface all at once. Otherwise, it just continues to warp in a different way than when you started. I was looking forward to hearing those island rhythms too!
On another thread, I asked for advice for reducing the warp in one record that I have. I think it was affected by heat somehow. My idea was to use a clothes iron to heat the record and press it flat. I laid the record on a paper record sleeve on a flat surface, then placed a microfiber towel over the record and then applied the iron (no steam). I went slowly and started out with low heat. The warp decreased but not enough to play it. So, I gradually upped the heat and it was still hard to get the record flat — If anything, it warped more on other parts of the record. I think it would take a special device that could apply heat and pressure equally over the entire record surface all at once. Otherwise, it just continues to warp in a different way than when you started. I was looking forward to hearing those island rhythms too!