Re: bad coals?
I've always noticed a smell when lighting the CH coals but honestly it never really bothered me. I've also noticed the discolored ash. The recent batch I have is better than the old ones but still.
The main reason I switched over to Starlights are cost and convenience. I can have a new box of 72 pcs in 20 minutes for about $4. They don't give off any oder, nor impart any taste and they last nearly as long as the CH coals. They seem to give off slightly less heat than a CH, but it's negligible.
Having said the above, I've also had some quality issues with the SL coals. Mostly inconsistent size and some cracking / flaking on occasion. They are also a bit messy, at least the ones I get. I even found a stone in one, it actually appeared to be a little chunk of iron ore believe it or not!