laundromat for big blankets?

[chhotii]

I wish to launder my large, thick comforter. Although the big washing machine in the laundry room downstairs claims to be a triple-load washer, I don't believe it's big enough to handle the comforter. I could cram the comforter in there, but I believe prior experience shows that it doesn't properly tumble, and the cleansing does not penetrate the inner folds.

What does one do with these?

Do y'all know of a laundromat with a REALLY REALLY BIG machine that can be counted on to deal with such items? Somerville/Medford area is fine, or the North Shore 'burbs, really; I have a car and can go places on the weekend.