I use glass bottles as they clean the best. I use hot soapy water then a 10 minute rince in my UC will usually get rid of most mix odors. If I use the bottle for the same mix I don't clean them. I in fact leave about 10% of the old mix in the bottom of the bottle and add fresh mix. This reduces the steep time to a fraction of what it usually takes. This is known as seed steeping. So if a mix usually takes 5 weeks to steep, seed steeping will steep the mix in 3 - 5 days.