I use a label maker. When I got a refurbished P-touch on brother.com for $5 I was afraid I wouldn't use it much. Now I am using it every day.
I label the carts, the bottles, etc. I am a labeling fool now.
If I get unmarked bottles I put a label with where it came from, VG or PG, etc.
If I made it, I reference the notes in my project book for that flavor.