You could try a local cleaners/laundry---they have large machines. Perhaps they would charge more than you would like.
Our local laundramat has huge machines---they eat quarters, lots of them. We use them for really big items as you are describing----just look around and make a few calls.
I do all my own stunts
03 Dolphin LX 6355, Workhorse W22, 8.1 vortec, 04 CR-V, Blue Ox, Brake Pro----Norm, Barb and
Doc(He's a PhD)