Sometimes it is the right tool-praise of grout brush
Just wanted to share.
Our bathrooms are original from the 1930s, and it's a bit of work to keep them looking clean as new.
I recently spent a insane amount of money...like $6... :-) on a grout brush with stiff bristles and an angled handle.
What a difference! The angle of the handle gives much more leverage when scrubbing. My bathrooms have never looked better. ( I scrub with Ajax)
Hope this can help someone else.