Allow to me differ in one regard: Woolite is not a soap, it is a detergent. Most sleeping bag manufacturers recommend that their synthetic bags be washed with a gentle soap. I would personally use some Dr Bronners and call it a day, but your other good bet is Ivory.

Ivory is pure.

Using a liner could extend time between cleanings, and a good airing can do wonders too.

Good ideas! Liners and a good airing it is.