Glycerin can be used to make a crude soap or other products.  It can be composted, especially if the methanol has been removed. Even with the methanol, it could probably be composted in small amonts.  Check out Matt Rudolf's presentation on biodiesel waste disposal (from the Piedmont Biofuels Coop). I've heard of folks mixing it with sawdust and making "logs" that can be burned in a fireplace, but I'd make sure no fumes are coming inside, because burning glycerin produces the toxic gas acrolein (also produced by burning wood). The University of Idaho Biodiesel researchers take their glycerin to the sewage treatment plant, where workers have told them it makes a great carbon source for the “bugs” (bacteria).  I have spoken to local sewage treatment folks, and they informed me that the flash point of the glycerin has to be above 140 deg F. Before removing the methanol, I had mine tested and it was only 70 deg F ! (and contained 19% methanol by volume).

The glycerin produced from using KOH as a catalyst stays very liquid, and can be mixed with water, which would reduce its flash point, allowing it to probably be ok to put down the sewer (not septic system). Once the methanol is removed, even the KOH glycerin gets kinda thick. Since it is pretty non-toxic with most methanol removed, it could probably just be put in the garbage, if you aren't able to compost.

Some companies will burn glycerin, such as paper mills or concrete companies, but they usually want it in large amounts. You might try advertising your glycerin on craigs list, and see if anyone has a use for it.

Do a search on glycerin disposal and check out the creative solutions people are finding on the chat forums (especially infopop).

The wash water can be sewered according to the folks at my local sewage treatment plant (as long as it's not too much, ie not commercial production quantities).