I recently bought one of the expensive scalpel types....yikes, must have a learning curve, as way too easy to cut your fabric.
Am I the only one who picks a couple stitches, cuts another a few inches away, and pulls out the bobbin thread? Much faster and no cutting of your fabric. I sometimes use a different shade on the bobbin just so it is easier to tell which is which. When I clip threads, I always leave the bobbin thread longer, just in case......... Especially a tip to use with beginning stitchers.