You have set yourself quite a task by waiting to do 2 years worth all at once. I usually do a batch whenever my tumbler barrel gets 1/2 full of clad. Seperate out the pennies from your quarters, dimes, and nickels and do them seperate or else all your clad will be pink! I use about 1/2 cup of aquarium gravel and then fill the barrel up to the 1/2-2/3 point with clad. Warm water enough to cover it and a squirt of dish soap (some swear by Dawn). Tumble about 4-6 hours to get them reasonable clean 6-8 for better results. I strain it off through a spaghetti strainer and dry the coins on an old towel. Save the gravel for the next batch. If your bank has a coin machine that doesn't charge a fee to use, you are good to go. Otherwise, I'd suggest rolling the coins so you aren't loosing a % of your hard dug $$. I keep my tumbler in the basement because there is some noise involved. Good luck and let us know how it all turns out.