Muriatic acid, vinegar, sodium hydroxide, sulphuric acid, nitric acid. ammonia.
Almost any acid or alkali will remove zinc.
Always releases a fume.
Fume can be deadly if inhaled.
Do not weld galvanised (even after it's stripped) with out plenty of fresh air flow and a respirator.
Always add acid to water.
Always neutralise acids before you dispose of them.
I also hear soaking in diesel for about a month will remove galvanize and turn the diesel into a jelly.