Currently, it’s possible to farm the Menagerie by collecting the loot when you beat the final boss then leaving the area you’re in, coming back and opening up the chest again. This is similar to a previous exploit in a lost sector on Earth near Winding Cove during a Faction Rally.
Once you have beaten the boss, open up the chest. Then head past the chest and through the tunnels and up. Once you come to a new area you’ll see the title of the area change in the bottom right-hand corner of the screen. Once you see this title change, turn around and go back down from where you came, slot in a new rune to the chalice and open up the chest again. As there’s a lot of time loaded onto the timer you can do this 5-6 times (depending on how many runes you have).
Destiny 2 fans were expecting the exploit to be patched, however, they haven’t done it yet so get as much loot as you can while it’s still here. There’s a good chance they will patch at reset.