In light of my recent ammonia problem I have become very aware of my lacks water treatments and care so I have stepped it up a bit and bought some food grade containers to transport water from the beach. These containers are only open through a 2 to 3 inch hole to pure liquid in and out and close with a special knob which you use a special wrench. That way there is no way of contamination. Now I need some help and advice on how to clean them. They used to have dr pepper mix in them and I need to clean them well. What can I use to clean them out because I cant get my hand in there to wipe the walls. Ideas?