How to rid body of excess vit. B1?

Stop taking it. "excess" vitamin b1 isn't known to occur. No toxicity has ever been documented & a dose that's considered unsafe to take has never been established. Even if you took a whole bottle most wouldn't be absorbed. It's not stored in our bodies.The elimination half life is about 1.8 days so if you don't take for 5 days about 85% of it will be eliminated.See http://ec.Europa.Eu/food/fs/sc/scf/out93_en.Pdf.