Four factors will determine the functioning of a detergent :

Chemical energy : pH and concentration. (Alkaline detergents remove proteins and fat; acid detergents remove mineral deposits like scale)

1. Thermal energy (Fat starts to dissolve as from 35 ° C or 95 ° F)

2. Physical energy (eg. a high pressure washer, manual scrubbing or "elbow grease", …)

3. CONTACTTIME : this will enable the chemical energy to do it's job. Moreover, it's the only factor that does not cost any energy, its Free Of Charge !