Dryer Balls Damage Dryer . It’s so simple that all you have to do is open your dryer and add three or more dryer balls in with your laundry. You can pick different complementary scents for each ball, or just scent one ball per load. Do Dryer Balls Work And Reduce Drying Time? VSGuides from www.vsguides.com Personally, i use 6 or more especially for extra large loads. 3 best wool dryer balls to consider. If you line dry the bottom, it will become flat, but the jumping balls in the dryer will blow it up.