I sold my rocktumbler, don't bother anymore. I wash the coins off in the sink. The silver/copper pennies and non-corroded pennies get dumped into the coin machine at my credit union and it is free, cuz I'm a member. The machine then gives me a coupon, which I can either deposit OR cash. The Corroded pennies get a tap 'er 2 with a ballpene hammer. I scrape the remaining corrosion off on the planter box outside, but a concrete sidewalk'll do fine. Some are even holed, but I just roll them up and deposit them into my account at the credit union. They told me that all clad goes to the mint to evaluate it's worthiness to be recirculated. Why should I tumble it for them? If they want it tumbled, they can do it their selves. Who are we to say if the coins are worthy or not worthy to be recirculated? It is government property and I'm just returning it, doing them a favor most times. I let the mint decide and I get my fee, .25 for .25, .10 for .10, .05 for .05 and .01 for .01 and BELIEVE me it adds up, even if the clad pennies are a hassle, you will FIND TONS OF THEM, GET PAID!