My last tenant has left heavy staining on the garage floor - as in something was probably spilled. I can't tell from the photo what it is, I doubt if paint unless it happened to be brown. It looks more like I would expect of something less dense such as a timber stain etc. There is nothing around the property that I can think of where this may have been used to give me an idea of what it is. There are a few dirty oil marks as well.
What are the best things for trying to clean, and not knowing what it is. What order would you try them? I'm guessing there is paint stripper in case it is the remains of a paint spill, hydrocloric acid, caustic soda (great for cleaning paint brushes in a tin, not sure about mixing and brushing onto concrete). Also need to make sure it does not eat into the concrete. Would you get away with brushing something on and hosing off or need to get a high pressure gernsy.
Here is a pic
What are the best things for trying to clean, and not knowing what it is. What order would you try them? I'm guessing there is paint stripper in case it is the remains of a paint spill, hydrocloric acid, caustic soda (great for cleaning paint brushes in a tin, not sure about mixing and brushing onto concrete). Also need to make sure it does not eat into the concrete. Would you get away with brushing something on and hosing off or need to get a high pressure gernsy.
Here is a pic