With four aggressive chewers, we are always washing, stitching, or replacing squeakers in toys. I will do a small load of toys every few weeks. I usually do them on gentle cycle, with detergent but no fabric softener (since that lingers on the toy). Then I always throw them in the dryer. Sometimes the squeaker fills with water, but usually, if you press it a few times, it will empty out.
The toys will never look as good as new, but I figure, hey, they're only dog toys that are going to get slobbered on, de-squeaked, and dragged out into the muddy backyard again anyhow. I don't really care how they look as long as the dogs enjoy them! (I think I wash the toys less because of how they look and more because I don't want my babies putting those yucky things in their mouths - how silly is that logic? )