I have a gas fireplace that blows a ton of cold air into my faily room with the thermostat. It is coming from the top front in two locations. One is the top silver insulation has a 1 1/2 gap in the front the cold air is escaping from - can I put the fireplace insert insulation strip up there or will it catch on fire?

Also where the grey slate hits the fireplace there is a gap in the sealant all the way around where air is ecsaping from - can I use the foam or is there something else that is non-flammable preferable clear since you'll see most of it?

Thanks!