What kind of solutions do you use for lens cleaning? I have found that pure isopropanol commonly suggested easily leaves some spots or stains after wiping with it. I have now tried a following recipe which is also suggested for cleaning stains from negatives: 90 ml isopropanol 0.5 ml 25% ammonia 9.5 ml water Works better than pure isopropanol and I hope the dilute ammonia is safe for lens coatings. Anyway, it still easily leaves drying spots and the surface seems to gather dust very easily. My chemicals and water were pure. I think some of the commercial lens cleaners have quite a lot of detergent in them, which helps to avoid visible drying spots and also leave a thic coat which prevents fogging. Prehaps I should add some surface tension lowering chemical like Ilfosol into my cleaning solution? Anyone with ideas or good recipes?