I have one of these, and it might work for 10-30 ml bottles of pg solution.I have found, that if you warm the bottle up a bit, then shake it you can get them re-mixed a bit easier. I have always wanted one of those miniature paint shakers, for this but never did get one.
Paint Shaker, 120v AC (micromark.com)
KAS
I tried to use it to shake my final mixed in bottle e-liquid with over 70vg, and that did not work out. Just didn't mix.
The paint shaker makes a pretty good amount of noise as well.