Hi Dr. M., I've been using the expired latex from Cementex for a little over a year now. I mainly use it for making latex heads, latexing wire creations using cotton and papertowelling and I love it. I've never had a problem with it. Each gallon I've purchased has been smooth and consistent with each order. When I ordered my first gallon of the expired stuff, the company told me that it has a chance of having lumps in the latex but only once did I find a quarter sized non useable lump. It is also reccomended that you don't open the container and work from the gallon bucket. I take approx. 1 pint of liquid latex out at a time and place it in an air tight container to work from. If you expose the liquid latex to air for any length of time it will harden.