Gargles For Ghusal
3 times is the maximum number so that one should not indulge in wasting water for Wuzu/Ghusal. Rinsing mouth is not mandatory but it is done to achieve completion in purity and is in accordance with uswa of the prophet (sws). Please refer to the following responses of Ghamidi Sahab for details: Discussion 13304 • Reply 37005 Discussion 31825 • Reply 31829 Discussion 32078 • Reply 32120