Cleaning up old discoloured tile grouting?

[bandooq]

We need an update.

 

[DineoM1]

Hi

I bought TC10 from builders warehouse to clean stains from my bath - it didn't work for me.

What is the reliable product that we can use. Please advise.

 

[greg0205]

^ Pine Gel and a fine scourer.

You can thank me later.

 

[longboy]

Aqua Regia mixed with 1 part water. Leave to soak for a few minutes then just wipe off.

(Always mix acid to water and not vice-versa)