I made a dolly out of a sheet of half-inch plywood and four swiveling wheels. I used 2 by 4s between the wheels and the plywood to get it high enough to get my jack under it. I jacked it up under the SF, released the SF, lowered it to the floor, pulled the jack out, and rolled the dolly with the SF on it out.
You need to be careful, because when the SF is released, it's unstable and wants to pitch forward. So it's useful to have an "assistant" to steady it and some blocks to put under it.
Here's a picture of how Gernold at SL-Tech does it.