I've been doing it for several years. In fact, the local road dept is trying ( with Glycerol supplied by me) different mixes this year on area roads. You first have to remove the Methanol, then neutralize the PH with vinegar. I've tried different ratios, but like 10 to 1 the best. 10 parts water to 1 part glycerol.
What you want, is the water to evaporate leaving the sticky glycerol behind to bind small particules together.