I find glycerin at Walmart or drug stores in the first aid section - near isopropl alcohol, witch hazel, etc. Not all stores will have it, but I live in rural NC and our Walmart has it, so.....
(this is the CVS version from their website - same size bottle I get at Walmart:
http://www.cvs.com/shop/product-deta...P?skuId=483707 )