Kerosene with a grunge brush (google--nice tool) and a dentures brush on top--hits all 4 sides in one fell swoop. Clean on the bottom run. Top is harder to reach. wipe excess kerosene off with rag, take bike for a good ride to fling out the remaining kero. Maxima chain wax sprayed on immediately after while chain is warm. No need to douse it too heavy. This will stick to the chain better than anything but there is nothing I know of that is completely fling free. I recently have been favoring Maxima chain lube instead of the wax. Flings more than wax but also, I notice the chain does not collect nearly as much dirt. The lube stays soft at all temps. Wax will not liquify in low temp riding so i don't know how well it is lubing.
Do not use WD-40 to clean----I have seen it cause degredation of o-rings on my old chain. It won't destroy o-rings after just a few cleanings but you'l see little black rubber fibers ticking out and stuck on your wheel. Never had that with kero.
A hot oil bath is probably best for off road bikes but with sealed oring chains on a road bike, not necessary and probably overkill. there is grease inside every link and I could see a long soak causing this to dissolve out. The non oring chains drag racers sometimes use might benefit from this.