Epoxy-based paint is strong, adheres aggressively, and is designed to be permanent; this makes it difficult to remove it from a porous surface such as concrete. However, there are several methods to remove this paint from concrete surfaces.
Steps

Step 1. There are two basic methods:
the mechanical (which consists of cleaning with a sandblast with a disc polisher) and the chemical. The various types of equipment required for the mechanical method are typically faster, more expensive, messier, and more dangerous (it is almost like an industrial process and is typically out of the budget of most readers). For the rest of us, the chemical method is the best.

Step 2. The choice of stripper can vary greatly depending on where you live
Most strippers contain methyl ethyl ketone and will work well on epoxy, but they do have some problems. They can give off gases, are toxic and flammable. Methyl Ethyl Ketone is the old standard and you may not find other strippers. However, there are environmentally friendly alternatives that do not have a very strong odor and are not as toxic. Some of these include Gp 2000 coating remover, DoradoStrip paint remover, and Soy-Gel paint and urethane remover. These strippers are also a bit aggressive, so follow all instructions on the can and be very careful. Most of these are flammable or can damage the eye in a few seconds. Wear safety glasses!

Step 3. Clean the surface and wash it
Open the doors and windows, because most strippers generate flammable or strong vapors and once you start to get your hands dirty with the sticky substance you won't want to touch the door to leave the room. A fan could also be very useful, but keep it away from the work area and make sure you have blocked access to the area you are working in.

Step 4. Most strippers have coverage rules and considerable soak times to remove paint adhesion
Read the label and follow the instructions. Do not rush. You will only lengthen your work time if you scrape the paint more than necessary. Use a brush if you want to spread the stripper over the surface by hand. If you have to spray it on the surface, you can use a manual spray, but the sprayer should be disposable. Strippers are harsh chemicals and are harsh on equipment.

Step 5. Work in small areas and to one side of the surface
You need to make the surface as clean as possible as you scrape (sticky, saturated paint) the area to control the mess. Don't rush with the stripper or you'll end up working a lot more. Remember to clean the stripper in the areas you've finished as you go along and every time you want to take a break. If you don't rinse the stripper off the floor well, it could interact with the glue that you will use later to resurface or reposition the rugs.

Step 6. Ventilate the area you have stripped for several days
Concrete is very porous and will likely release fumes from the stripper that it absorbed while you were working. Congratulations!
Advice
- Concrete will spark on steel tools, so read the label. If the product or its vapors are flammable you will need to buy non-metallic spatulas.
- You should treat your clothes and tools as if they were disposable. Most strippers are very strong for any surface.
- Follow the directions on the label and be prepared to wait hours or even most of the day for the stripper to work. Epoxy-based paint is strong. You will gain nothing by speeding up the process.
Warnings
- Wear protective gear. Watch where you put your hands (most strippers will damage almost every surface you touch).
- Ventilation is very important.
- Think of children and pets when stripping paint. Most strippers are aggressive, flammable, and relatively toxic. Many can cause irreparable damage and change your life in seconds. Keep children out of the work area!