Stronger acid. Muriatic will do the job. Be sure to do it outside and then
rinse, rinse, rinse some more.

Popeye wrote:

Just recently came into possesion of a 40gal corner tank with an all
glass lid. The lid has a lot of deposits on it that are proving
difficult to remove. I kept it wet most of the day with straight
vinegar and the deposits are winning. Any suggestions as to what might
remove them?

Thanks
Brian