2.+Use+half+as+much

To test the claim that the amount of detergent needed is different between detergents we:
 * 1) Set up a gradient by measuring 0, 1, 2, 3 or 4 drops of each detergent into a glass and adding 200 ml of freshly boiled water.
 * 2) Knives were smeared with lipstick
 * 3) Give a 5 minutes soak in solution, mixing for 10 seconds of every minute.
 * 4) At the end of 5 minutes score the result for the amount of material remaining on the knife.