Everyone knows that Dark Elixir is hard to come by. Of course their will be those who say it's easy just rob the drills, however this guide is for any town hall 10 who's had enough experience to count the cost of upgrading heroes. Combined, it takes about 450 building days and nearly 8 million Dark elixir to max them. Despite the fact that it's not 100% efficient to farm DE with DE troops, it decreases build time and if done right the profits are enormous. So haters beware, this system works.
It's just bloonion farming ladies and Gents.
Troops: 20 loons and 70 minions.
Spells: 2 Rage, 2 Heal, 1 Freeze
Try not to use all your spells in one raid. It will save you lots of elixir and allow you to raid roughly twice an hour if you set up your build right and can conserve even 4 balloons using 16 when possible.
Type of Base to raid:
Your'e looking for bases with only one inferno covering the DE. Your'e also looking for level 4-5 air defenses and X-bows pointed down. Maybe low level X-bow's pointed up.
All I do is:
1. Pick the side closest to the DE (duh) spread my balloons along that side and immediately drop all my minions behind. As per typical loonion raids, the balloons soak up most of the damage. Don't even worry about the enemy CC/heroes. The balloon's will soak up a bit of damage and the minions will kill the cc. Rarely will the CC ruin the raid. All archers are the worst. Larger troops like Drags, wizards etc will be taken out by your minions as they attack the balloons. I don't even worry about CC/AQ and I've had great success.
2. Close to the nearest inferno guarding the DE, drop the rage/rage's to speed their attack, one to two heals spells slightly ahead and over the inferno tower followed by the freeze spell to stop the damage and heal the partially damaged balloons.
At that point I think one maxed balloon with a rage dropping one bomb will destroy the inferno tower. (Don't quote me on that I read it somewhere and from my experience I think it is accurate). Again, only use the spells you need to, this all happens very quickly and it takes time to gain the skill of assessing the raid accurately and not wasting spells and troops.
Once you get into crystal 1 you will find town hall 10's holding 2500-3500 Dark Elixir easily. The league bonus gives you an additional 200-400 DE depending on what league you're in. If the balloons are building while you are raiding your build time is 32 minutes and with a boosted spell factory, your spells easily keep up. If you conserve troops/spells finding raids on inactive bases that's awesome. (yes haters, they are still their occasionally).
The reason why I put this for town hall 10's is because I believe the best Dark Elixir is in Crystal 1 & up. Most town hall 9's, although they might be skilled enough and raid often enough to get the DE, unless they spend it right away, they won't keep it. They become the food.
Town hall 10's can profit 1500-2500 per raid using this. It works well for farmers who raid every half an hour - 10 raids a day. Both will benefit. If you still have upgrades to do, you will find your elixir and gold will grow enough to afford an upgrade or two from each resource per week. It all depends on how much you raid. The point is it is constant and keeps you in the league's where the Dark Elixir is. You do use a small amount of DE per raid but you get so much back. I've easily farmed 14,000-60,000 in a day using this. 14,000 with under 10 raids and 60,000 with 25ish raids.
On top of that you should have maxed your drills which will bring in about 7,200 per day. I decided to buy $100 of gems and boost my drills and spell factory. That will put it up to 14,400 from collectors.
With the combined farming and collectors I can EASILY bring in 45,000 DE per day.
So why would you want to upgrade heroes so badly? For those young town hall 10's that have never been close to master one...at that level the heroes tip the scale and get you the two star victories. Once you've maxed your town hall you'll want those heroes up near 25 or greater. If you've neglected them there are many ways to get it done but I find this way the most effective. I hope this helps.