I am not an expert but this is what I would do.............
If you say 20ml of 18mg nic juice..........if you added 40ml of vg or even 50/50 pg and vg at 0 nic (you can even use the vg you get at Walmart)...........you would have a 6mg nic juice.
The flavor would also be diluted but honestly, the juices I have done this to were quite enjoyable. And I had rather not waste if I have an option.
Here is a link to the calculator that helps me figure out my nic if I am combining. I hope this helps.
