Steps to remove the tar.
Removing tar from concrete wall.
The first thing i would try is a sandblaster.
This is the most efficient and inexpensive way that i ve found.
I would not use them as the fire hazard is so extreme.
When diluting always add acid to the water.
Put on all of your protective gear before you begin working with muriatic acid.
Dilute the acid to the desired strength using the label as your guide.
Follow the label s recommended ratio.
Scrape the tar off with a drywall knife.
Test it for effectiveness.
To clean the tar from your concrete floor with muriatic acid first put on all of your safety gear.
There actually seems to be a dearth of information on efficient ways to do this.
If you are lucky a tool rental shop may have a small sandblasting kit that works off of an air compressor used by carpenters.
The sooner this is accomplished the better.
These are all distilled hydrocarbons that can soften the tar.
Check the label carefully before you open the bottle making sure.