The Gideon Handheld Steam Cleaner is a little powerhouse. It might not be a huge, or expensive machine, but it is pretty powerful for its price and usability.
I was able to clean my kitchen grout lines and the ones in my bathroom too as these are a nightmare in my house as I leave in an all brick house with no wall insulation hence mould Is a big issue and a contentious battle. This little rocket steamer had no problems cutting through most of that built-up mould that doesn’t seem to go away with a regular brush. I think after a few goes fingers crossed it will disappear completely.