Did you have someone stain your concrete floor and it just turned out horrible? If so you might be interested in knowing how to remove the stain. Depending on what type of stain was used there is two possible ways to remove the stain. If the stain was a water based acrylic stain (paint) you could use a paint stripper to remove the stain from the concrete.
If however the stain was an acid stain or an acetone dye, you will not be able to use any type of strippers to remove or lighten the stain. You will have to grind the concrete with either a hand grinder fitted with a diamond wheel or use a stand behind grinder. Grinding will remove any type of stain that was used, so if your not sure I would begin with grinding the concrete. You want to make sure you don’t use a very aggressive diamond wheel or you will leave a rough profile.
When grinding concrete make sure you have a vacuum and respirator because the concrete dust is very harmful to your lungs. Hope this helps!