For lead use nitric acid if you have some handy. If not or if you’d
rather not screw around with acid you can remove both the lead and
the WG mechanically. (I hate working with acid, no matter how
careful I am my fingers itch, such a sensitive human being)
First you have to identify just where the goop is. For the lead, if
its an older repair, you should be able to see it, dull grey Grind
it, sand it, polish it, whatever you like, just avoid breathing it.
To check if you got complete removal just heat the piece up to lead
solder temp. It’ll get shiny for a minute. Grind some more if needed.
For the WG, heat it also, but just enough for it to discolor, then
grind it, whatever.
It might not be a bad idea…before you do the actual laser welding,
go low on power and a wide aperture and just go over the areas in
question. It should show any minute residual goop but shouldn’t
materially effect the surface finish of the Plat.