Toddler throwing clean Tupperware in the sink

Ok haha this is my latest issue with my 16 mo old. All our cabinets are child proofed except the Tupperware one and we let him play in there. His latest thing is taking my clean Tupperware and pushing it up into my kitchen sink. So I’m ending up having to wash all this Tupperware because he throws it in the sink with dirty dishes. Is my only solution to lock him out of the Tupperware or does anyone have any suggestions 😅