Step 4 · Allow Cleaner to Dwell
Allow the cleaning solution to sit undisturbed in the toilet bowl. For moderate stains, a dwell time of at least 30-60 minutes is recommended. Given the assumed severe nature of the stains, allowing the vinegar or commercial cleaner to work for several hours, or even overnight, will yield the best results by giving the acid ample time to break down and dissolve the tough mineral buildup.