I keep a fine tapestry/cross-stitch needle handy, and use it to go in under a stitch, pull it up, and snip.
Then continue carefully along the stitches, doing the same for each.
Sometimes once I get started, the others come out fairly easily.
If your stitches join onto FMQing that you want to keep, try to start in the midst of your work,
so that you can have top/bottom threads long enough at each end to tie off and bury,
to protect the work you are keeping.
Good Luck ..... and {{hugs}} to those GrandLambs!