50 could be separate from one another and separately set or positioned within the base 16 the powder detergent cup 48 includes an outlet opening 54 in the end wall 42 adjacent the back wall 36 the bottom wall 44 slopes downwardly from front to back and end to end toward the outlet opening 54 such that powder detergent contained within the cup 48 can be flushed out the opening 54 a liquid detergent cup 56 mounts on the powder detergent cup 48 the liquid cup 56 includes a back wall 58 a front wall 60 opposite end walls 62 64 and a bottom wall or floor 66 a lip 68 is provided on the back wall 58 front wall 60 and end wall 64 the lip 68 engages the walls 36 38 42 of the tray 34 to support the liquid detergent cup 56 within the powder detergent cup 48 the liquid cup 56 is shallower than the powder cup 48 such that the bottom wall 66 of the liquid cup 56 is spaced above the bottom wall 44 of the powder cup 48 a hollow siphon tube 70 extends upwardly from the rear corner of the liquid cup 56 adjacent the back wall 58 and end wall 64 the bottom wall 66 slopes downwardly from end to end and front to back towards the siphon tube 70 a siphon cap 72 fits over the siphon tube 70 the siphon cap 72 has an inside diameter which is greater than the outside diameter of the siphon tube 70 the.