What is it? Seems to grow out of some wooden areas in the room. I’ve tried peroxide and bleach. Would a steamer help? Sorry in advance for the bad picture quality.
That’s a chair? It shouldn’t just be growing there randomly. So you live in a highly humid environment? Eesh.
Sounds like it could be some mineral growth. This happens a lot in humid area. I’ve read magnesium is especially susceptible to this.
I had given it a thought that it may be crystallized salt from the marine air, but it doesn’t dissolve. The clusters are almost hydrophobic in water at first but end up as a suspension when stirred around, i.e. not soluble.