Wasteland King Taxi Trick

Here are the step by step instructions.

Fill your normal infirmary with T1 Taxis - These are the cheapest units to heal, also they cause the least amount of damage to the commander that is assisting you.
Send your least valued units to die at a tower - I train T10 - T 13 Cars for this, Because your regular infirmary is full, every troop that is sent to the tower will count as a casualty.
Use the Fast Comeback buff to drastically increase your might - You will get a 300% training speed boost for 120% of the troop might that is sent to the tower.

Here are some key points that will make this strategy effective

Don't over commit - Don't send too many troops that you don't have enough resources or speedups to retrain the troops that were sent.
Slowly heal your troops in deep healing - You don't need to use diamonds to heal your troops in deep healing.
Don't send troops to alliance infirmary or to permanently die - If you are concerned about a whole march of troop permanently dying, then heal your taxis.