There is an even faster way to do the above boosting methods with a silver account (or any second account). It is not necessary to play the full challenge time. The account that is losing the challenge can accept the challenge and immediately quit. The losing score will be 0. The account that is wining the challenge can set a score greater than 0 and then immediately quit. For example, in Astrosmash, shoot one asteroid and quit the challenge with a high score of 10. Each challenge only lasts about 5 seconds.