Weighing a chin

I have a nice digital scale, that weighs in grams. What is the best way to get a chin to sit on the scale?



Tonight I ended up putting her in a pillow case. After subtracting the weight of the box I set her in and the weight of the pillowcase she turned out to be 509 lbs.



But then she came and stood on the scale without and she weighed what looked if me between 6oo and 7oo



So....how do you all go about measuring your chins weight ?