A five gallon plastic bucket, a four inch diameter aluminum duct, some short sections of 2 x 4’s, and four spacer screws to align the duct with the center of the bucket.
The duct should extend to within 4 inches of the bottom of the bucket. You pour 2″ of water in the bucket, connect the clothes dryer hose, and start your clothes dryer.
It also does a wonderful job of catching lint.