It’s probably one of the questions I see the most when it comes to glitter cups. How do you keep the rim clean after adding epoxy. A lot of people use an exacto knife to scrape epoxy off after it has cured & that does help for final clean up, but keeping your rim clean throughout the different steps makes the whole process so much easier. Take a peak at how I clean up the rims on my glitter tumblers.
These types of make up wedges work great for cleaning the rim too https://www.amazon.com/gp/product/B01CJVL8OY/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B01CJVL8OY&linkCode=as2&tag=sweetsights24-20&linkId=1c17f6f92e7564a69d4783d101eae382