Walmart Humco works for me.
No walmart? Try a local Cake shop. They usually state "96 USP GRADE" on the side. I was using these, but I didn't know what the 96 meant, possible %age?
I thought it was the Cake Shop Glycerin causing me to be dizzy, but it was the level of nic.
I thought of going back and trying the HUGE jug (8oz) of it sitting in my cupboard, but I haven't run out of the first of the two I bought from WalMart yet, and it's been months!
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Side note:
If you go to the Cake Shop and see LorAnn flavorings, be sure to get a (eye?) dropper. You can use the dropper to suck the prefilled cart juice out (stick it on the side of the polly filler and plunge), put that in a container and then mix it all at the same time. Refill them the same way until you have other options available. Fluff the filling back up to the top after the fill.