Ball Grinding Method

The ball grinding method refers to when you stack up on tons of balls, with the Random Rooms Glitch.
 * Suppose you get a Break Point (or some other High Net Gain stage with more crystals than obstacles), finish the current stage and then enter the next stage.
 * Keep quitting, closing the game, restarting the game (i.e. Perfect Method) and then briefly pressing Resume (otherwise you will return to the Main Menu), then wait for another stage with many crystals.
 * Keep doing this, taking advantage of any High Net Gain stages, then you will eventually have thousands of balls.
 * I recommend you do the random rooms glitch and hope that you get a Checkpoint 2 or 3 room (the title says Checkpoint 3 saved or Checkpoint 4 saved) and then restart on the checkpoint (you need Premium though)
 * Note that although the Random Rooms Glitch works in Training Mode, the method will not work above 500 balls. Use only when you are running low on balls, or want to stash on multiball.

Alternative methods

 * You can cause a Repeating Checkpoint Glitch, and then smash the crystals, obstacles, etc. Then, close the game and reopen it. If your stage is classified as High Net Gain, then you will get more and more balls.
 * Using the preserved status glitch, keep restarting the High Net Gain stages when nearly at the end, then continue when the player is satisfied with the amount of balls.
 * This is easy when you use a grinder on any checkpoint, pass with all crystals and not crash.

Don't waste the balls!