There are products on the market you can buy locally at your Walmart or hardware store. The recommended ones are CLR and Clorox. If you use one of these products and a little elbow grease with a sponge the stains will come out with ease.
Kaboom! Kaboom!
scrubbing real hard with soap and water
The best product to remove hard water stains from bathroom fixtures and fittings is Mr. Clean Magic Erasers. They come in different sizes and textures for different jobs.
You can find the removal hard water stains at some store like homedepot or lowes. You can also find it on some websites like amazon or ebay for the good price but have to wait for shipping time.
this is very hard to remove, you can try a solution of vinegar and water, but in the long run, throw the mattress out.
A soft scrub of an SOS pad removes water stains from glass very nicely. Just don't scrub too hard.
Whink Rust Remover will quickly get rid of rust stains and best of all it requires no scrubbing.
Because its yellow
Try CLR. It removes rust from many things without damage.
get powder, salt, soap, and water. Add the salt, soap, water, and the powder rub hard on the leather then let dry in sun or hot room
Diluted bleach can clean stone brick stucco. Often gentle water pressure can remove hard water stains on stucco as well.
MR: CLEAN MAGIC ERSER or a product called CRL. Soaking the block with vinegar may also work.