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.
Rose water is also used to treat pimples and to get rid of blackheads. The rose petals have antibacaterial properties and are soothing to the skin. Mix rose water with lemon juice and applying to the skin twice a week . Another way to use rose water is to boil petals in water and steam the face for ten minutes. 9. Get Rid Of Itchy Scalp & Induce Hair Growth: As rose water is anti-inflammatory and reduces dryness it it really good for dry itchy scalp.