My solution is to tamp down the tobacco, and slide a cleaner in the stem, then cover the bowl with my palm for a moment before placing my pipe in a pocket. If it is a quick stop I skip the pipe cleaner.
I hold my palm over the bowl for a minute. Unless it's a very new bowl there should be enough room between the ash and your palm to keep you from burning yourself. Alternatively you could just stick your tongue in the bowl and the moisture of your tongue mixed with the ash should induce vomiting which would probably distinguish the ember....