MooShoo doesn't cover his poo at all, but just scrapes the inside of the covered boxes (I have 5 boxes for 6 cats), which can be very annoying at 3 a.m.

Mollie Rose, being the lady that she is, digs to China before she goes and again afterwards. Then keeps on by scratching the edge of the box making a "thumping" noise (also annoying at 3 a.m.).