how can i bring pencil rotten of a computer monitor assured?

Answer:

Depends on what type of monitor it is! Dont steal ANY advice until you know this detail!
If the pen speck is not on the display screen itself, later anything that cleans plastic is fine. Try an eraser first. Try a damp cloth first, consequently add for a moment bit of mild soap if you need to. Make sure not to capture any water onto the display blind. If that doesn't work, try a little pin polish remover.
3M Electronics Cleaner from Office Depot and a good scrub.
get a sopping cloth, not dripping wet and scrub Hard!.
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