I ran across this blog post about how to wash felt, specifically about hand-washing it. There is much more good advice there than what I had to offer:
How to wash felt, wool felt foods, soft sculpture & toys.
Some of the main points are:
- Handle your felt with care when wet. It can fuzz and pill.
- Squeeze your felt item when washing it rather than rubbing.
- Air dry. It may feel stiff until handled and played with.