@cassie0528 I recently got a fanny pack from REI so that when walking my dog I would have a place to store her filled poop bags and not have to carry them in my hand. I have a plastic bag in the fanny pack that acts as a liner so that the pack doesn't get really gross. So far it has been immensely useful for picking up other garbage along the trail, especially in the wetlands where the tides bring in a new batch of floating trash daily. If I am hiking and have a backpack, I normally stash a small dry bag in the outside for trash. The dry bag helps if you pick up aluminum cans that aren't quite empty or other waterlogged grossness. 

PDB
he/him/his