I originally posted this in home improvement forum but figured it would get more run here..

See the below pictures. Would anyone know how to remove or cure these type of concrete stains?

I assume they are due to moisture issues - for example, the first spot was due to a wet cushion I sat down for a few days under my covered patio to dry off. It's been like that for months. The other areas are more exposed to the daily elements.

In Houston. Concrete slab is 5+ years old.

TSP - TriSodiumPhosphate- will clean pretty much any stain off that will come off. You can buy it in the paint area of your choice of paint store. I use the granule/powder.

Work it with a stiff broom and wash off. DO NOT get in contact with painted or stained items - it will change their color.

https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Ftse1.mm.bing.net%2Fth%2Fid%2FOIP.cBuT67-0A4MtjDkWQYqu-AHaHa%3Fpid%3DApi&f=1&ipt=c9a03699c7f2c23a97cb20d1be9beb1799f5d4e699a941cdd8f00dfad49de4a8&ipo=images

Do you have a power washer? Might help

I do, power washing doesn't solve the stains / spottiness.