Now that my printers are enclosed with carbon filters, I print more ABS than anything else.
My way isn’t very scientific. I use a splash of acetone on paper towels, and wait about 40 minutes. I understand the right way is to use a clear polypropylene or glass container so you can sit there and watch it, but I don’t have that kind of patience.
One light surprise for me was that if you have sanded layer lines off, you’ll see them more after smoothing. This was really visible in black in my Replacement KROMEX flour lid even after two attempts at smoothing. I assume this is due to anisotrophic residual stress.