I used to boil them (with vinegar & water) in the microwave, but then the constant hot steam broke the microwave!! (at least that's what the repairman said!) But I didn't have a lid on or anything, so I am sure that made things extra steamy! Now I just use a teapot and pour the boiling water over the nebs (which are in a separate bowl with the vinegar)! Good luck! Happy steaming! Post your tips!