Historically, my bathroom an inferno of toxic fumes using Domestos bleach as I tried to clean my grout & tiles. I am sure that I have even lost some of my sense of smell from the overuse of that stuff!!
So, what I needed here was a bleach alternative, that was in a paste form to clean that ugly grout! I have tried a few options using the old vinegar/bicarb trick which basically does nothing – the acid and base principal must be true in that they counteract each other
There are a couple recipes you could use to tackle this job like the Laundry Butter Cleaning Paste but what you need is the inclusion of Hydrogen Peroxide!
Great news, we are now stocking Crystal Clear Percarbonate which is Washing Soda & Hydrogen Peroxide that has been premixed & dried - the key ingredient in Napisan/Oxibleach. It's highly concentrated, so a little goes a long way. You just need hot or boiling water to activate the hydrogen & watch stains disappear before your eyes.