Dude just have 1 key in your consumables and fill the other slots with glimmer consumables, house banners, telemetries, heavy synths, etc etc you get the point. Then when you open a chest you will only get glimmer, keys, planet resources, and legendary engrams. You can even fill up your materials so that all you ever find in those chests are glimmer, engrams, and keys. I don't know how people haven't figured this out yet. I only regret not knowing before I accumulated 50 special synths but thanks to invective bounty they will be gone shortly. Hope this helps.