Removing a backing
 

I made a quilt top in blues, greens, yellows, and creams that I had a jelly roll for....turned out pretty good. What I didn't have was a matching backing and for some reason thought a cheddar/cream small print would work. Spray basted and pinned together and now I hate the backing and want to change it. It has not yet been quilted. Have you ever removed a spray basted backing, washed it, and could use it again?

Yes, you can do it ... but ... it depends on how heavily sprayed you did it.
And too, what sort of batting it is.
A gentle tug, and your backing may lift easily, or may not.
It may pull chunks of the batting with it though.
Especially if you heavily sprayed it.

If so, and you're not so much worried about salvaging your cheddar fabric,
... it may be easier to just bury it, covering it with your new backing!

Once removed, no problem ... just throw in the washer
... as the spray baste is meant to wash out of the fabric.

I would remove the pins, lay it out w/back facing up, water bottle spray the backing. Let it sit a bit, then start gently removing the backing fabric. Leave the top & batting to dry. All parts good to go.

I think covering it up with a different backing fabric would be much easier and less chance of something going wrong.

I have to agree that the easiest solution is just covering the backing with another piece of fabric. But also think about how many times the back of this particular quilt will be seen. If this is a gift for someone else, quilt it up as is, and gift it. No explanation for your choice needed. If it is for yourself, how much do you hate it? Enough to go to all that trouble which does not have a guaranteed outcome?

Running your hand and arm between the layers can help unstick the layers and helps with distortion and pulling up chunks of batting. Go slowly and gently. Please don’t ask me how I know this. LOL

I agree with the others that putting another backing over the first would be the best way to do this.

Until fairly recently, most quilts had a muslin backing.

While some people like everything to match, I'm more of a use it up and move it out kind of person. If the quilt has blue in it and I have a large piece of blue, it'll get used. Mind you, my quilts are scrappy style - so lots of fabrics in each color - but if it's in the same color family, I'll use it. If I don't have enough (most of mine are big bed quilts), I'll piece a backing with several fabrics.

While it's doable, I'd be thinking hard about whether it's really worth the extra work. And money, as you'll have a piece of fabric that won't be used.

If you haven't yet stitched anything together, the backing should just peel off. Spray basting is temporary and designed to wash out of the fabric so you can wash the backing fabric and use it cut into little pieces in blocks for the front of a new quilt. You will figure out the best way to peel off the backing once you start and there are plenty of suggestions here. I'd be sacrificing my arm to the innards.

Maybe do very big stitch basting and then soak the unfinished quilt. Spin it out and see if that back might be loose. Covering it up with another back will add weight to the quilt. Will it be a problem when it comes to the actual quilting process? Unless this is for competition, I'd just be happy that it has a back and carry on.......