Drink all her booze, especially any unopened craft gin or special wine she may be saving for special occasion
Leave used, snotty tissues everywhere
Run dirty fingers along the walls
Eat greasy fries with loads of ketchup, don’t wipe your hands, then go turn on all the lights in the flat being sure to leave behind great ketchup finger marks
Put your feet up on the furniture and walls - wearing your muddy trainers
Use her car without asking and return with only fumes in the tank
Spill nail polish on her coffee table
Make up, clothes, dirty dishes, fake tan, money all previously covered