Test the grout when doing the estimate.
Clean with alkaline cleaner first.
Then apply acid.
If the grout fizzes with acid it isn't sealed or coated with wax.
If it doesn't fizz then use a little stripper and see if anything changes.
As far as method goes, use GM first always.
Spray grout lines first, then dwell for 5-10 mins.
Then right before rinsing, mist the whole floor again with GM.
Use a spinner. 150° at 1200 - 1500 psi
If there are spots that didn't clean up, treat with acid and clean again.
If the grout is badly stained then sell color sealer.
This is why I spend time doing a thorough estimate inspection.
Clean with alkaline cleaner first.
Then apply acid.
If the grout fizzes with acid it isn't sealed or coated with wax.
If it doesn't fizz then use a little stripper and see if anything changes.
As far as method goes, use GM first always.
Spray grout lines first, then dwell for 5-10 mins.
Then right before rinsing, mist the whole floor again with GM.
Use a spinner. 150° at 1200 - 1500 psi
If there are spots that didn't clean up, treat with acid and clean again.
If the grout is badly stained then sell color sealer.
This is why I spend time doing a thorough estimate inspection.