Hi Buddy, sanding will get rid of it quite easily but be very careful on that precious spalt cap as you can sand through without noticing before it is too late.
In the PUP cavities, do the PUP's still have enough clearance? If so, nothing to worry about, in fact you may even prefer the dark background down in those holes. If not, maybe scrape out from above with a very sharp chisel or Stanley knife blade. The aim is not to touch any wood, just scrape off the Timber Mate as it will be almost like a plastic film on top of everything. Once you get back to the timber switch to light sanding, probably 240 or 320.