How much tea tree oil do you use?

Tea Tree Oil should never be used pure.

It can easily be mixed with most other house hold oils to form a weaker solution.

I use Grape Seed Oil or Sunflower Seed Oil or Olive Oil.

How strong mix you want depends on what you want to use it for or against.

It has been shown in studies that solutions as low as 5% will effectively kill off Head Lice and Scabies. Some contradicting stories regarding this though.

I have with success used 10% solution against scabies.

Tea Tree Oil has got great anti fungal and antibacterial properties. It helps healing wounds and improves the scar tissue. For this, I would suggest 5% solution.

I would probably start off with a 10% solution regarding fungal infections on feet though.

This oil should not be taken orally or be used on very sensitive skin like ears, around eyes, around penis/scrotum/vagina. That might sting and it could be a rather unpleasant experience, especially around eyes.