I tried the PGA and it didn't get rid of the previous flavor for me so I went to putting them in the freezer, that's right, the freezer. After I get any residue out of the bottles, caps and droppers I let them air dry and then through them into an uncovered plastic container and just keep them in there. Try it, I thought it was crazy when I first heard of it but it does work. Takes a couple of weeks though. I reuse mainly 6ml bottles so it doesn't take up much freezer space. 15 & 30ml bottles I try to keep with the same main flavors when I reuse them...mint to mint strawberry to strawberry, etc.