For years I have used plain old roofing tar to seal cleft grafts. May be a bit messier than the
the fancy products like Doc Farwells, but a heck of a lot cheaper. The trees seem to be quite
happy with it, and my graft takes are in the 90's)
For whip-and-tongue and similar grafts, I use electrician's tape, (which I slit down one side in
the Fall to avoid girdling. No need to remove the tape, and in fact best left in situ because
otherwise it tends to pull off the bark. It will eventually fall of.)