Home Improvement
I would use a commercial concrete cleaner to remove any bad oil stains and then a solid sealer. Sika should make both of them and be available at the big DIY stores in the masonry section.
A well-sealed concrete countertop is a great work surface in a kitchen, though you might have to reseal it every year.
I looked into this and it seems there are 0 food safe concrete sealers available in Belgium that I can find. Strange.
Maybe find a marble and stone dealer who does kitchen installs and ask them?
I would look into grinding and sanding it flat and a resin coating to seal the surface. There are YouTube tutorials to DIY it if you are price conscious
Since this needs to last for 2 years you can add a thin epoxy layer to perfectly smooth out the surface and make it hospitable.
Can you upload a photo so we have an idea?
I realized I never took any great pictures of it since this was lower priority, but here is a few that I have that include the bench to give an idea https://imgur.com/a/KgiqHrC
You get a resolution? I’d buy a cheap wet grinder and some sealant. You can polish it smooth and all chamfer (?) the corners of you so desire. You can also look at putting a fresh coat of concrete on top of its super pitted.