So I've been sleeping in my bag a lot more and I've noticed that my loft has been decreasing and that the shell material around my head has gotten a little discolored. I blame it all on my oily skin. I need to wash my bag, yes I know but here's my question:

How do synthetic bags/quilts fair with oily skin?

You need to wash your bag periodically. Synthetic still utilizes lofted fibers that can be degraded by your body oils. I know some people are concerned that washing is going to ruin their bag, but if done properly it will extend the life and renew the performance of your bag.

This page on Western Mountaineering's site has good instructions on washing/caring for and down bag

http://www.westernmountaineering.com/index.cfm?section=product-tips-and-care

You can really stretch out the time between washing by following these two simple steps:

1. Wear long john's and liner socks to minimize skin-bag contact. Mine are silk - comfy and light weight.

2. After each trip -- wipe down with a clean, wet hand towel -- esp. the hood and foot bed -- then air out to dry before storing.

Ben said, "1. Wear long john's and liner socks to minimize skin-bag contact."

A big +1 on that!

Wash up before bed. Sunsreen, bug juice, your own juice all got to go.

I agree that this "oil issue" applies to all bags other than those awesomely comfortable flannel-lined, rectangular bags with outdoorsey patterns in the liner... well, maybe those, also.

Anyway, as noted above, cleaning one-self and avoiding skin-to-bag contact is a big part of keeping the bag clean and "not-greasy". For teenagers with oily skin and Scoutmasters with greasy Italian hairs (like 10 left), it's often a good idea to wear a skull cap or bandana to sleep. It's the backpackers' antimacassar.