When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Best way to check the floats (once they are clean) is to put them in a glass or metal container of gasoline deep enough that they can float, see if they float at about the same depth after a couple hours. Outdoors is best.