i have 25 count empty Tylenol/Ibuprofen bottles that i save exactly for this reason. I also bring a couple of single rolls of Rolaids, a blister pack of Sudafed, a small tube of hydrocortisone cream, doesn't take up any room at all.
I have a travel sized container of liquid laundry soap that i bring, very handy. The laundromats on board are very limited to the brands of detergent to choose from. The laundry tabs also work great,packed in a ziploc bag.