For a silent auction, I would donate money in the amount of the materials I would have used. I would have no problem donating a quilt for a raffle, but I would never do it for a silent auction. Have seen too many posts on the QB about quilts going for $15 or $20 that way. (If you search, you may find some of the old threads on this topic.) Many quilters said both the charity and they themselves would have been better off just donating money.