I've been mulling over making some of these things but was concerned about at chimney sooting up burning these things.

Any personal experience with these? How easy are they to make?

If any fuel burns completely with sufficient air then there will be no unburned particles like soot.

Spence, I dont kake logs but I do mix it with sawdust and burn it, I also mix the dregs from settling wvo with saw dust and burn it also.
I just dump sawdust on top of the stuff in a 55 gallon barrel and use a paddle on my Milwaukee 1/2" drill motor until it is the desired consistency.
After that I just use a small fire place cleaning shovel and scoop it in, it burns hot.

So you just slop it into the fireplace?

Oops, no, it goes in the wood boiler, I put it on top of the wood in the boiler, but I mix it up so it is really dry, it would be nice to come up with something to solidify the stuff, I have thought about putting them under pressure on a tube but I think you would just squeez the oil or glyc out of the sawdust.

quote:

it would be nice to come up with something to solidify the stuff,

It does solidify all by itself at about -5°C. Having it already in empty milk cartons makes it easier to handle once it's solid.