Mixing - Get some good vanilla eliquid of the same nic level (I like Backwoods Brew). Mix the bad liquids with vanilla. Vanilla is a great fixer upper. Some other good fixer uppers - if you want more sweet try a caramel. If you want less sweet try FreedomSmokeUSA Cocoa - which is dark, strong and almost bitter - it will really fix up too-sweet tobaccos, or you could turn a sweet overdone fruit liquid into a chocolatey fruit. A good fixer for juices not sweet enough are sweeteners - Tasty Vapor sells a bottle of safe sweetener - it is sucralose aka splendex diluted 10% w/ PG.
Steeping - If they are perfumey or powdery smelling, uncap, pop out the dropper and set somewhere safe from kids, pets and spills (and away from heat or sun) for several hours to overnight. Then put the dropper back in, recap and try. If still not good let sit for a while.
Armageddon - Put them in an Armageddon box in case the supply of eliquid is cut off by laws, FDA, disaster, etc
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