How do I effectively try a patch test?

The inside of you elbow toward your wrist (closer to elbow is best)
is the closest skin (sensitivity-wise) to your face.
1. Place a good amount of the product on that skin area and cover it with a gauze covered with
a waterproof tape so it stays on and doesn't get wet (I use bandaid water block plus bandaids
because they are small bandaids with waterproof tape all the way around - very discrete)
2. Wait 2 days to verify if you will have a reaction, but if you want to be SURE, wait 4 days.