Somewhere on your sofa — usually under a cushion or on the frame beneath the skirt — there's a tag with a single letter on it. That letter is the manufacturer's cleaning code, and it's the first thing any competent upholstery cleaner looks for.
W means the fabric can be cleaned with water-based solutions. S means solvent only, and water will leave rings or shrink it. WS means either method is acceptable. X means neither: vacuum only, because any liquid will damage the fabric or the dye.
The reason this matters is that the mistakes are not recoverable. Water on an S-code fabric leaves permanent watermarks around the edge of the damp area. Too much moisture on any fabric soaks into the cushion foam, and foam that stays wet develops a smell that is far worse than what you were cleaning off in the first place. And a fabric that isn't colorfast will move dye the moment it's wet, which is why we test an out-of-sight spot even when the code says water is fine.
There's also a distinction worth understanding between dirt and body oil. Loose soil, crumbs, and pet hair are dry and come out with proper vacuuming before anything wet happens. The dark patches on the arms and headrests are something else — that's accumulated skin oil, and it needs a treatment that breaks oil down rather than more water. Cleaners who skip the dry stage and go straight to extraction end up making mud out of the dry soil and doing nothing about the oil.
Microfiber, which is what most sectionals sold in the last fifteen years are made of, is usually the most rewarding fabric we clean. It looks hopeless when it's grey and matted, and it comes back remarkably well because the soil is sitting in the nap rather than dyed into the fiber. The trick is low moisture and grooming the nap back in one direction afterward, so it dries evenly instead of drying blotchy.
If your tag is long gone, don't guess. Tell your cleaner and let them test — that's a two-minute job, and it's a lot cheaper than reupholstering.