Apply 91-99% isopropyl alcohol to the end of a q-tip just enough to saturate to cotton. Don't allow alcohol to pool on displays you want a almost instantly evoprating flim on the outside of the display not a puddle on the inside.
You can do the same thing with a micro fiber cloth, just avoid longer strand fluffier automotive microfiber cloths
Plastic tools like spudgers can be used to gently scrape dirt and debris, micro fiber cloths are always useful. And the pointy tweezers from ifixit are okay on some things but be careful around flex cables and other sensitive compents.
Always wear latex, vinyl or nitrile gloves when handling internal compents for the best results. It keeps used phone crud off your hands and keeps your skin oils off the phone parts.
Wipe away on the metal plate just don't over wet with alochol or apply much pressure.
A clean repair is a repair done right!