I have a shoe box for self catering type hols, including CP.
I fill a 100ml bottle (like your airline bottles) with washup liquid from home, that usually does the week. And a handful of dishwasher tablets (I bring about 5 so I can run it daily if we need to).
A pair of silicone oven gloves. A new washup sponge, a couple of new Jcloths (leave both behind). 2/3 bin bags, handful of Ziploc sandwich bags (for picnics, leftovers in fridge, wet togs etc). I also have an old box of icecube bags that I being, easier than trays on hols and they'll eventually all get used!
A 250ml bottle of olive oil (I have an old bottle that I just fill at home). A salt, pepper and a chill mill (the glass bottles from the spices aisle that have a twistable mill built into the lid). Sachets of ketchup from McDs or similar (and any mustard, mayonnaise, soy sauce or vinegar I find beforehand too) - instead of bringing bottles that I'd want to bring remains home. If you are not massive users of sugar, gather a handful of those from coffee shops ahead of time too.
Matches, nightlight candles, firelighters, (and a couple of firelogs and a portable BBQ for CP).
Chalk. Pack of cards. A board game. Favourite DVDs.
I have a small sharp knife, a small wooden spoon, a corkscrew, tinopener, and a small chopping board in my shoebox too - I've been stung too many times about being unable to cook in SC accommodations!
We do a supermarket shop after we get off the ferry before getting to CP - and I include toilet roll, kitchen roll, tin foil (small roll), ground coffee (I bring a stainless steel plunger from home that stands up well to getting thrown around), and basically a food shop for most of the week including a few treats for us all, lots of fruit (and limes!), breakfasts, the makings of maybe 3-4 lunches and 2-3 dinners, and a decent bottle of gin and a couple of boxes of nice wine (boxes transport easier and we have enough self control to stop after a couple of glasses each per night so last better). And some nice toiletries (including the ability to have a lovely relaxing bath one evening! see nightlights! and wine!).