Obtain the proper kind of hydrogen peroxide. You can use hydrogen peroxide to clear acne using one of two methods: in a cream, which contains a concentration of up to 1% hydrogen peroxide; and in âpureâ liquid form, which should contain no more than a 3% concentration.
3. Pitch : Pitch is the theoretical distance a propeller will move through the water for each revolution. (i.e. a 21pitch propeller should move a boat forward 21 for each revolution, assuming there is no slippage).
An Example of a roof pitch would be a 6/12 pitch which means that the roof rises 6  for every 12 inward towards the peak (or ridge). There are two suggested ways to measure a roof pitch. The first is from the top of the roof. Simply mark a level at 12.