Some of my t-shirts (the ones that are 100% cotton) started developing this strange armpit stain:
it makes the fabric feel brittle and crusty around it;
it can't be washed off with water and detergent;
it can't be scrapped off easily.
Now here's some information about the environment my clothes live in:
our water is moderately hard (60-120 ppm);
I use a deodorant that has the following ingredients:
- I sweat a lot and our climate is quite dry.
I was thinking I'm dealing with a boring calcium carbonate deposit, but I don't really want to start drowning all my stained shirts in vinegar without first knowing what I'm dealing with. What do you guys think it is and how would you get rid of it?