The laptop itself is clean with no signs of any tar build-up.
Smoke contains very fine particulates that stick everywhere.
HItting any surface of that computer with a clean cottonball soaked in alcohol will probably invalidate your claim of “signs of tar build up”. They may have cleaned the exterior that way, but probably didn’t clean the interior.
Generally, replace your fans. They have tiny crevaces that capture the smoke particulate, and their function of moving air puts them in contact with plenty of it.
You could take the fan apart and rebuild it, but it’s usually easier and cheaper to just replace them. Using cotton balls and swabs soaked in rubbing alcohol, wipe down all of the surface area of the mainboard and case. Repeat until you don’t see any discoloration of the cotton.
Some methods suggest doing the same thing with vinegar after the final alcohol wipes are done. In my experience, it doesn’t help much, but probably can’t hurt.
I wasn’t serious. But this thread just reminded me of something that happened to a friend of mine, where his leather jacket smelled like an ash tray and someone suggested to put it in a freezer for x amount of days.
I used to have a tooth that caused pain, so I removed it and the pain was over. A colleague complains that he feels a lot of pain in his leg. So I advised him on my method to remove the cause of the pain. Then he will no longer feel pain.
You know, you could actually do this. If the soap is non-conductive, and the water is distilled, this would work fine, as long as you allow it to COMPLETELY dry off before use, since distilled water can pick up metallic ions from the solder joints, and actually become conductive.