Big wall anchors can turn into an incredible cluster if you don't do your best to keep everything tidy. An excellent way to do this is to keep the lead and haul ropes contained and feeling smoothly by using rope bags.
It may seem like one extra bit of a necessary gear, but it can keep your big wall belays absolutely more manageable and less tangled.
You have are several options.
Low budget: Ikea bag. Reinforce it with Gorilla tape if it starts getting beat up. Should last you for a trip or two.
Metolius Wall stuff sack, size large.
Fish Gear makes some great rope bags. fishproducts.com > Product catalog > Big Wall
double and single Fish rope bags: