Question
I heard some plants like urine (lemon trees, etc.) so I watered my potted mint plant with urine. Then , I found out they prefer it in small quantities, and diluted.

All the branches have fallen to the ground and look dead, and the stems have gone hard, dry and brittle.
It was previously a thriving plant, and I am very unhappy - I feel like I have killed a friend through negligence.

Is there anything I can do to help that plant recover?

It is in a medium sized pot (pot about 10" tall, 10" diameter), on a balcony, with light coming from the east.
I was watering it almost daily.. about half a glass of filtered tap water.
Then, for several days over about a week and a half, I gave it half a glass of urine. It took about a week and a half for it to start to die.  

Answer
Daniel,

On any plant if you are going to use urine, you should use it once a month. It is very high in nitrogen. Using it undiluted over a wee and a half would damage any plant! The only thing you can do is take it to the kitchen sink, remove the drain tray from under the plant and run water through it slowly to wash as much of the urine out as possible. Let it run through several times to really wash it out. There is a chance if the roots have not been totally burned that they will send out new shoots. In the future only use urine as a fertilizer once a month or stick with Miracle Grow which is easier to control and has other nutrients besides nitrogen that will benefit your plants. Good luck.

Darlene