Yea, that's what i do...more or less, just leave them and tin cans in a plastic bag for them to collect.
Actually I do disagree on this one, it is only promoting vagabondism.
And all too often I see (or foremostly smell) the said gentlemen on Warsaw public transport, a plague for all other passengers.
It is a mystery to me how a bar of soap can be too expensive, and a carton of pseudo wine cheap enough?
Same as I do not give money to the gentlemen offering to "keep an eye on your car".