Wife has been making these for years, I think she got the idea from girl scout leaders training almost 20 years ago. I provide her oak shavings from a surface planer. The oak seems to work best and the planer makes a great size chip for lighting and soaking up wax. She buys blocks of wax from the hobby store when they go on sale. She purchased an old second hand metal coffee pot that is solely used for this. I set her up in a large open concrete drive outside and she will make about 5 years worth at a time.
They are mostly waterproof, store easy and will almost always work to get kindling going. Not a guarantee, but much easier and safer cleaner than my old redneck way of putting the whole camp at risk of injury. We bring a few along with us on all outings.
Yes, she is awesome, and these work well.