Flower rosin, especially buds pressed without a filter, usually contain some plant matter, and most definitely contains fats, waxes and lipids in the finished dabbable product. As amazing as flower rosin smells and tastes, a bit of your yield is these types of plant matter. Because of this, there are some causes and effects of vaporizing this material, one of which is a dirty nail! In stark contrast, material that has been highly refined or sifted, leaves little residue on the nail which is due in part to it's purity (distillate, 6-star hash, isolate). Does the nail have to get dirty? So how does the nail get dirty when vaporizing flower rosin? By vaporizing the flower rosin at hotter than ideal temperatures. Not swabbing up the waste (melted fats, lipids, waxes, non-active matter) soon enough, and also suboptimal cleaning regime. How to keep the nail clean using flower rosin? It all depends on your nail, some are much easier to clean than others. Usually keeping your nail surface temperature in the <450F range will vaporize all of the terpenes and cannabinoids while leaving the rest of the waxes and such to be swabbed up usually with a cotton swab. Using some distilled water on a cotton swab will steam clean the nail. Having done this on both SiC nails and quartz, with no problems. Whenever your nail starts to get too dirty, deep clean. For a heavy user this could take a few days to a week.