tree in picture is honey locust, black locust only have thorns near the leaves. Black locust make one of the longest lasting fence posts, more dense than the honey locust. Only tree superior as a post is Osage Orange.

I should imagine that any commercial stump rot will work; all I have ever seen were saltpeter with a label. Let the stump set several months before applying the the stump rot.
NaCl never did much for me unless I was trying to kill the soil.

 

Well, not sure about locust, but we used catalpa wood from one that got struck by lightening. It started to die, and being dangerously close to the house we cut it down. Those fence posts have lasted for a long time with no sealant on them that I know of.

Honsetly, if you aren't going to wait to pull the stump, just hollow the heart out, and light a fire in it. The fire will burn/hollow most of it away, at least enough to be pulled out with the tractor, or the truck. Probably one of the easiest and fastest methods to pulling a big stump out.

 

Some of you may know I've been out of action because of a damned nasty chest cold. In the last few days it has let up off of me a lot - to where I can breathe right again!

I may have a second grapevine going, further back in the "URUSHIOL ZONE". I'll be going after it as soon as the weather warms, the ground dries, and the winds die down. But the coming week is expected to be thunderstorm city, so I bet I'll be twiddling my thumbs for a while yet.

Good news is I got a new weapon! A 'pole saw' that has an eight inch bar electric chainsaw mounted on a collapsible control shaft that is six feet collapsed down, twelve feet extended. The bar and chain are both made by Oregon....

What I'm going to do with a lot of this trash is a good question, pile it up and bury it under a few truckloads of dirt is what I think is going to be the answer.