To wash felt
Dry cleaning is the best method to safely clean felt, without damaging it.
Hand washing is by far the safer way to clean felt, as you are in control throughout the entire process. Begin again with a shallow bath of cold water and add a mild detergent. Consider adding a dab of lemon juice to the soak for both stain lifting purposes and its pleasant scent. Submerge the felt and allow it to soak.
Once you have let it soak for a few minutes, use your fingers to massage the fabric. Once you have finished kneading the fabric for a few minutes, wring it out gently and lay it out on top of a clean towel.
To dry felt
Lay a clean, dry towel on a flat surface. (The top of your washing machine or dryer works well for this purpose.) Lay the felt flat on top of the towel and let it air-dry. Do not put felt into the dryer. This will warp and shrink the fabric.
To iron felt
To iron felt fabric, set the iron on a low, wool mode, and iron the fabric continuously from left to right.
Do not iron the painted area directly.