Скачать или смотреть How to fix mouse button - intermittent or loose contact - without soldering a new switch

(the video is the switch inside your mouse that the mouse button presses down)

PROBLEM: Your mouse double-clicks when you only click once (single click). OR: While you are dragging files/windows they drop before you let go of the button.

CAUTION:
1) The spring (the copper-colored thing in the video) is very thin so be careful once you get the top cover off the microswitch.
2) The white button is loose and will fall out when you take the top cover off, so do it in a place where you can find if it falls.
3) Make sure the white button does not fall inside when putting the microswitch's cover back on -- if the button falls inside the cover, and you try to put the cover on, you MAY BEND THE SPRING. I reinstall the cover with the whole thing upside -- so gravity keeps the button in it's slot.

SOLUTION:
Open your mouse, then take the top off the "miniature snap-action switch" (a.k.a. microswitch ).
Split a toothpick in half (so that it is SKINNIER - not shorter) -- I use a box-cutter or x-acto knife for this.
On the contact area, put a few drops of denatured alcohol (perhaps 90+% isopropyl will work).
Use the toothpick to scrub the contacts (I spend about 20 seconds on each contact).
For optimal cleaning, blow the switch off with compressed air.
Put it all back together
TADA!

TIPS:
1) Most microswitches I've seen have bendable tabs on the ends of the top cover like in the video. I used the blade of a box cutter knife to get under the tab and lift it. Once I get one tab off, i just tilt the whole cover (like in the video) and the other tab comes off. EDIT: I think i just bent a spring by doing this (just the very end -- so it still works) -- apparently if you lift the side that has the white button first, the cover's clip can put pressure on the very end of the spring, so i recommend lifting the other side first, or putting a little pressure (away from the unit) on the clip as you tilt.

2) About getting the spring back in if you knock it out... [!!!OLD METHOD REMOVED!!!]
Thanks to Ashur Alagondar for his comment about my old method being a bad idea, and giving a better way (insert cleaned end, then opposite end, then use something small to push the middle curved part down until it clicks into it's notch).