Hello Sir, Actually My Whole Body Skin Is Covered With

Hello sir, Actually my whole body skin is covered with dirt layer, I don't know how but this is very irritating, my hands, my back all.. Due to dirt layer, my skin look irritating and blackish, when I rub on my skin,dust particle come out.. This is from 1 year. Before that my skin is so smooth and clean. But due to this I lost my confidence to face someone.. Please give me best solution for it