Grouting, what is really brilliant at sorting it out?

[TrickyD]

There seem to be lots of products, I need something ideally from Amazon that I can send to our lovely tenants who will soon be leaving but have allowed black mould to build up along the bath. They might be OK about having a go at it themselves if it is easy to use and effective.
I would pop round myself but the house is 96 miles away.
The grout itself is ok no leaks.

Do you mean the grout or the silicone sealant?
Dettol mould and mildew cleaner is good

Hg mould spray is excellent and the only thing I have found that works and keeps it away for months. B and q sell it.

Neat bleach is brilliant. Put "sausages" of cotton wool or kitchen paper along the sealant. Soak with neat bleach. Leave for at least twelve hours.

second HG mould spray, it's magic. Might need two goes if it's bad.

Maybe google this first but we used cheap neat bleach held on overnight with kitchen towel. Worked a treat.

hg mould spray is brilliant. Makes it look brand new.

Third the HG mould spray with the bleach sausages for the sections of sealant that are still mouldy.

Neat Milton (or other bottle sterilising liquid) kills most mold.

Bleach actually dissolves grout over time so be careful!

If you mix bleach with bicarb to make a paste, you can paint it on the grout and then rinse after a couple of hours. It stays in place and removes black mould like magic.

I use white vinegar and scrub it with a toothbrush. Does the limescale at the same time.

Thanks everyone, HG mould spray is winging its way to our tenants. I hope they have time to use it, they plan to move out next week.