I keep a cork in a film cannister which can easily fit anywhere. You need a lighter as the cork will require burning often during the application process to maintain a build-up of soot. I light the end and let it burn well for a moment then blow out the flame. Use the cork like a marker to apply. I'll use it on exposed areas of the face, ears, neck, back of hands, etc. You can make hard dark lines and you can blend the edges and make differing shades. It works well to break outlines making it difficult to pick you out from the surrounds. The cannister allows you to store the cork without getting soot everywhere while carrying.
I normally can remove the majority of the cork soot using nothing more than a few baby wipes if without running water.
Best:)