How many bottles are you washing at a time? Anyway this would be no bueno washing dishes in the shower is even more of a faux pas than using the bathroom sinks.

Paper towel can work in an emergency but i don’t think that method would last weeks of 2 kc a day.

I think i need a cheap disposable container I can mix the shakes in.

This is what i gave so far: Plastic Deli Food Storage Containers With Leak-Proof Lids 48 Pack, 32 Oz | Microwaveable Airtight Container For Soups, Snacks, Meal Prep, Salad, Ice Cream | BPA-Free Kitchen & Restaurant Supplies (48) https://www.amazon.com/dp/B07TG8JQNG/ref=cm_sw_r_cp_api_i_j8AzFb51XZJTE