Spark ignition gasoline and compression ignition diesel engines differ in how they supply and ignite the fuel. In a spark ignition engine, the fuel is mixed with air and then inducted into the cylinder during the intake process. After the piston compresses the fuel-air mixture, the spark ignites it, causing combustion.
1 If your skin is too sensitive, dilute tea tree oil with some baby shampoo. Add 10-20 drops of tea tree oil to 1/2 cup of baby shampoo. Use this daily to wash your scalp and hair till you get rid of itchy scalp.  You can even massage diluted tea tree oil to your scalp.
Do not use shampoo at this stage. Wash your hair with shampoo the next day. Make sure you do not use too much pepper, it may cause your scalp to burn. Clears up a stuffy nose and relieves cough: Due to its antibacterial properties, black pepper is a very effective natural remedy to cure colds and coughs.