We have deposits on bottles in our state. With a nearby college town, we put up signs that we would pick up bottles and cans on X day, at X time, at these listed locations. We also stopped at some frat houses who were glad to contribute sacks of bottles and cans. Our group was Pony Club, had adults attending the kids, so it was safe.
We collected LOTS of bottles and cans this way, then took them in to redeem. I think we filled 2 two-horse trailers, truck beds and half of a 4-horse trailer, after about 6 hours of time. Then more time putting them thru the machines to redeem them. We did very well with our collection, to add to our treasury. The money helped pay Rally fees, so kids could attend for minimal cost. We also hired Instructors to visit, give lessons, rate the kids for moving up levels. We also invested in lumber to let parents build club jumps for practices.
I thought it a very good money raiser, for the time spent. No one was enthused about selling stuff.