Urac is waterproof, get a little on your clothes during a glue-up and it will be there for the life of your clothes no matter how many time you wash them.
Get your urac from the Nelson Paint Company on line. Shipped for the same price as most charge before shipping. A pint will last you a long time. It does have a shelf life, if you keep it in the frig it will last up to 3 years.
In my opinion Urac is the best although others mentioned will work just fine.