However, if your GBL is colored at all or cloudy (it should be clear and colorless) then you should look into purification methods, as your stuff is unfit for human consumption. (When you purchase GBL or BDO, please ask for the assay documents so you can be informed of what the impurities are that could be present, and their acceptable limits. GBL used as a solvent for plastic thread spinning may not be as strictly controlled in impurities as GBL for ACS chemical reagent usage, or food-grade GBL.