1st internal investigation of a 29 w/?

OK so I woke up yesterday am and my touchscreen was not working.
Checked FAQ and sure enough it was racing off to the side.
Tried the toothpick but no go.
With a little hesitation I opened it up, just the screen and its back.
I'll make it short and won't talk about the removal of unnecessary screws and forgetting the latch with 1st reassembly and just say that disassembly must have released enough pressure for whatever it was to fall out because it is working fine now.
My question is what is the best thing to clean the internal screen surfaces, reverse side of TS and actual face of LCD (DN alcohol?) and where is the best place to find replacement screws.
I was very careful and all screws are present but I can see that there magical disappearance is possible.
Also does anyone add extra protection to there toughbooks when reassemble; extra sealants, home made gaskets, thread lockers.
Thanks

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