GHB can be safely pH adjusted with no problem. You cannot destroy it by making it "too alkaline" or "too acidic". But if the stuff you have tastes "corrosive" and smells like GBL, I would bet money there's still unreacted GBL in there.
The lazy man's solution to the problem, is make a solution of about 10% baking soda (sodium bicarbonate) in water, and dissolve your dose of GHB in approximately a shot glass of bicarbonate-water. That will help neutralise any acidity present. (Don't drink large amounts of bicarbonate water, it can mess with your stomach and eventually kidneys - like eating a lot of salt). If you are even lazier, simply diluting the GHB in 10 times its volume of water will help (even if it is a little unpleasant to get down)
The more involved solution is to get some food grade lye (for making soap), and some pH paper or universal indicator. Make a solution of 50% lye in water (weight by weight). Stir it well until it all dissolves, and add it *drop by drop* to your GHB. Test the pH after every few drps by putting a single drop of the GHB mixture on a new piece of pH paper (don't dip the paper in your GHB). You want it to be about 7-8. If you overshoot and it goes too high (too alkaline), you can add citric acid or vinegar to adjust the pH down again. This will also destroy unreacted GBL and turn it to sodium GHB.
Be very careful with lye and lye-water. If you've ever seen Fight Club you may know that lye causes rather painful burns. They're not really joking, if you get concentrated lye water on your skin it will turn all the fats into soap! This results in an itching, tingling sensation quickly changing into an intense, painful burning as your skin cells dissolve themselves. ALWAYS Wear gloves and eye protection when working with lye. Don't ever drink something that has a pH above about 9. It will burn your throat.
