Go to the cliffs of old Russia by the water. There are millions there

I’ve gotten glimmer fast by performing missions in PvE. Any extra loot and crates scattered in the map often have glimmer between +125 - +135. Any spare guns you find can be dismantled for gun parts and glimmer. When dismantled they range from +6 - +15 a piece depending on the power of the weapon and rarity. Specifically, when you get the item called “Ether Seeds” which is dropped on missions. Those items provide a boost and with every enemy killed, they will drop extra glimmer for 10 minutes. So when I get that kind of item, I then go through a Strike mission so I can rack up kills and money at the same time.

Thanks guys.

Use ether seeds at the point in The Devil's Lair where you use a ghost to take down the barriers. Waves of Fallen will come and you'll get a healthy share of glimmer from that.