The guy brought a laptop for cleaning, then when he took it, lighted a lamp in the screw and looked at something carefully.
I asked what he was looking there and the guy explains that he was wearing a laptop for cleaning and he was just washed with a compressor without disassembling it, now he is gluing a little plasticine into the screw hat)
And, by the way, a good way to know if you have a note or not.