Any suggestions on a good way to clean grout - besides just scrubbing the
hell out of it?

Thanks!

A grout cleaner that has a mild acid, or bleach if it is black like
mold. Try bleach first.

I use bleach and a toothbrush.
Pat

My tile installer said to use muriatic acid and water. The amount of acid was
small. Maybe 5%. He said wash the floor with it, then rinse. Good as new. I
haven't done it yet as the tenant is still renting the place. :-)
Read about all the cautions on using any acids. Duh