In the first for dusting, grind thoroughly in a blender and store in a tightly capped jar. Don't try to use a food processor for either of these. (The cornstarch acts as an anti-caking agent)
In the second, again grind thoroughly and store the same. This can be use when powdered sugar is called for as an ingredient IN the recipe and will give some bulk.
I use the first often on Lemon Bars and some Bundt cakes. The second, I use to make my own version of Swiss Mocha Powder, which I like in my coffee. Omitting the cornstarch, I mix it with Ramstadt-Breda Rich Dark Cocoa and store in a jar. Add one tsp. of that to fresh ground/brewed coffee and sneer at Starbucks! LOL BTW, I use Dunkin' Donuts regular blend beans. They're killing Starbucks with it...(The Ramstadt-Breda Rich Dark Cocoa is available at preparedpantry.com It's VERY good for this and baking)
For OTHER International flavored coffee powders, grind sugar-free hard candies such as peppermint, butterscotch, hazelnut etc. Sweet n' Low has a range of them. I make gifts of these to Diabetic friends for Christmas along w/ the recipe so they can make more for themselves. They make great gifts for your Diabetic or weight-conscious friends. Pretty simple. Dry non fat milk powder, non-caffeine instant coffee granules for those that only drink that, sugar-free candy powder and some Splenda if you want sweeter.
Jolly Rancher, Werther's Original, Crystal Light and Lifesavers all also have these and most are available at Amazon.com