Tonight I made a nice "menthol" flavor for my 510 that tastes very similar to, but cleaner than, the menthol flavored cartomizers sold by Njoy for the 2N1.
So, now I get a really clean menthol flavor with the fabulous vapor of the 510, and it cost very little.
Here's my "Minty Menthol" recipe:
1 part unflavored E-Juice (whatever brand you like)
1 part McCormick's Peppermint Extract (yes, the kind you can find @ your local grocers. (1 oz bottle - $4.62)
1 part Vegetable Glycerin (Humco brand from Walmart - USP -6 oz bottle $4.12 after tax)
1/8 Part distilled water (as close to free as you can get - $0.93 for a gallon)
This mix creates a very pleasant "menthol cool" sensation. The throat hit will depend on the E-Juice you use. I have not tried the menthol crystals, but that is next on my E-Cig to-do list.
I made a 0-mg Mix without any E-Juice just to see how it would taste, and was surprised to find that it was quite pleasant. So, I could see myself vaping this if I ever get to a point down the road where I manage to wean myself off of nicotine altogether.
Don't let the McCormick's name scare you. After doing a lot of research over the past month or so, consensus seems to be that most non-fruit extracts are safe as long as they contain no food coloring or sugar/sweetener (safe being a relative term since no long term trials have been conducted - so as always, you vape at your own risk) . The McCormick's label lists the ingredients as Alcohol (89%), Oil of Peppermint and Water.
I have noticed quite a bit of snobbery towards McCormick's on a few different forums. You can pay a fortune for some LorAnn flavorings if you like - but I wouldn't waste your money.
Since it does contain Oil of Peppermint, I would advise cleaning your atomizers each night. Simply blowing them out with Canned Air works wonders.
I hope you enjoy.