I used Sodium Percarbonate to wash my beer bottles for my home brew (available from the home brew shop), and put it in the dunny in the van as well, I have since stopped washing my beer bottles, I just rinse them after use and before re filling rince them with Milton baby bottle cleaner, I find it got rid of the chemical taste. Now when we were at the Tamworth Country Music Festival in January the sodium Percarbonate was not even close to the task in the extreme heat and a stationary van, I have since gone full chemical (the green one septic safe) and find it works way better, I just watch the specials at Supercheap as they seem to be the cheapest.