Put these under the fake coals that are in my propane fuelled coal effect fire. I used them to top up similar looking stuff that was there already. They appear to work as expected, but I'm no expert and so not really sure what they are supposed to do. Initially there was a bit of an odour when the fire was lit the first few times but that seems to have diminished now. My only gripe is that the pack contains an enormous amount of product. You only need a little, and you are left with a big bag of stuff to either store or discard. An option to buy a smaller amount would be better.