The white stains appear to be a combination of soap scum and calcium deposits from hard-water. You can scrub the walls using a suitable stone cleaning product to renew the original appearance. Sealing of most all natural stones is strongly recommended but sealing isn't the problem. The stains are topical and will occur no matter what. More frequent maintenance of the walls would be in order. From the photos the tiles do appear to be travertine or possibly limestone. Not the best choice for a shower when it comes to maintaining the surfaces. After cleaned and thoroughly dried the stone should be resealed.

GardenWebber, The short answer is, yes, you can get it out. But it's going to take some work. One way to tackle it if your cushions are removable is to get yourself some big, thick garbage bags, go outside with a wet/dry vac, put the cushion in the bag and suck all the air out of the bag until the cushion is entirely flat as a pancake. You need a good strong vacuum to get it super flat. I'd use something like a ShopVac. You'll want to do it outside b/c you don't want to be bothered with the expense of the super fine dust clogging up a HEPA filter on a fancy vacuum. You may have to repeat the garbage bag trick a few times to make a dent in the dust. The problem with furniture is it uses fine cell foam as the cushioning material. That is the same stuff they use in the vacuum pre-filters to trap dust. So you're basically cleaning one big filter. Every time someone has sat on the furniture they have forced the dust deeper and deeper into the foam. It will take some work to bring it all back to the surface where it can be sucked away. For the rest of the piece of furniture, you're probably going to have to punt to some form of wet cleaning - i.e. 'steam' cleaning to get all the dust out. As a previous poster mentioned with the wet microfiber cloth for cleaning hard surfaces, basically you're going to have to make fine mud and suck it out. The trick will be to use a machine that flushes as much water through the fabric/foam as possible. I personally use a Hoover SteamVac for our furniture and dining room chairs. It would be a good place to start but it doesn't have the best suction. Remember you have to get as much water back out as possible and dry it quickly or else the foam will mold/mildew. Think of the drywall dust as embedded dry mud and that should give you a good handle on what it's going to take to get it back out. Wet cleaning is the fastest road to cleanliness for these kinds of issues. - IT Geek

dust between the planks should have been cleaned by your gc up with a vaccuum before any cleaners were applied. use a vaccuum. If a vaccuum doesnt work then the cleaning solution made them stick and you can try wiping out every joint with a white cloth and a plastic putty knife with a white rage wrapped around it. Be careful not to mar the finish.

If you decide to vaccum it, and I don't know of any other way to do it, you can use a shop vac. but you really should get a high density, disposable paper bag to put in the vac. It really does make a difference. Otherwise the finest dust just comes back into the room. After you've vacced and if things still seem dusty you might have to go over the walls, ceiling and floors with a damp rag. I do the walls and ceiling wiht a rag tied around either a broom or a dustmop.