Look away all you chisel purists, this gets ugly.
This is a Marples chisel, at least 30 years old, possibly 60, but a very sharp and useful tool.
I actually do use this for the correct purpose, but I also sometimes use it for paring off almost set glue from the sides of joints.
I must have unknowingly put it away without wiping off the gooey adhesive, because when I got it out for the next job, this is what I found;
This is the reverse side;
I used the whet stone to remove it all, thinking it was just on the surface, but look how deep those pits are;
I might have to get the Jet wet sharpener out to deal with this.