Never use more than one. Cool down is a myth I've used one at each boss in challenge and have gotten an exotic drop each time once other times I've gotten nothing. I usually use them each strike sometimes with a drop sometimes with double and sometimes I can go 10 strikes without anything. This may be coincidence but the more you change up what your doing strikes crucible , challenge taken bosses you have better luck . If you sit and grind the same thing I can burn through coins fast. Cool down is a myth run 3 strikes do bounties change characters rinse and repeat seems to work great .

Boots is all i need for 335 but cant get them at all lol had 4 helms and primaries drop the grind continues....

They work 1 at a time. Even bungie has said it's useless to use 2 or more. No matter what myths you've heard, cool down is not known. Every theory I've heard has been debunked by many, including myself. Examples: Theory of waiting 15 minutes after a successful 3oc use, for another chance. I know people who used 1 during the brothers, got a drop after the first brother, popped another immidiatly, then got another after 2nd brother death. Theory of when to pop. I've gotten a drop while putting it on a second before the boss death. I've gotten a drop after putting on the 3oc the night before, then using it the next day. Every numbers theory I've ever heard was debunked one day with me and my friend. Ever heard of a double drop? 2 exotics on 1 coin use? Theyre pretty rare to get. Well I was playing crucible with my friend. We used 1 coin each every game. 5 games down, no drops for either. So 6th game we put 1 each on and head in. After the game my friend got a double drop. And so did I. We both got a double drop on the second game. That should be imp9ssible in the world of rng. After all my research. And usage of coins. I've found there really isn't a clear way to use them. It's a numbers game though. Keep a 3oc popped at all times, is the best answer. But yes, it seems waiting 15 or so.minutes after a success, isn't bad. Because the chances of getting 1 after another is possible, but very very low. As per the rewards, again not completely rng, but don't understand how it works. I got 9 primaries in a row over a 3 week spread of using 3ocs. My friend got nothing but boots in an entire month, which included 13 exotic drops. Again, the chances of us both getting that many same in a row, is extremely low.

Try this next time. Wait till boss is almost dead,then activate the coin. I believe there is something about using coins at higher risk levels. I've gotten many exotics this way. And several posts have been put up about this method.

Use one at a time, space out usage, and switch between characters. There is a cool down on 3oC. Plus your drop rate goes down when using them against the same ultra repeatedly. I use them when fighting taken champions, running PoE 28 or CoE, the occasinal crucible match (hate crucible) and nightfall. Barely touch strikes these days.

You are using them 1 at a time right?