Another thing you could do is to hand wash this in hot water in the sink. I just bought this device for hand washing, the Breathing Mobile Washer. It's the stupidest looking thing. It looks like a plunger with baffles on the end. I thought I was throwing my money away. But when I got it, it does everything the company claims it does. You put clothes in a gallon and a half of water, agitate it for two or three minutes, rinse it in clear water and briefly plunge it again, wring it out and hang it out to dry.
Darned if this thing doesn't work! It got my son's grungy pizza delivery shirt that was black and just about ready to walk away spotless. It cleaned the embroidered work logo patch and even got out some of the set in stains left from those expensive HE front loader machines at the laundromat. He texted me to thank me, amazed that it got out the pocket stains from his ink pens. I have a white work shirt for my food industry job that I'm supposed to keep spotless. It had ground in dirt and food stains left from the machine that I couldn't get out, and I've tried all the detergents and spot removers. My shirts were impeccable after just one use of this invention.
This stupid little device cleans my clothes better than those fancy machines, saves me time, and money. I imagine something like this would be great for felting as well, since you'd have better control over the whole process.