Lately, whenever I turn on the fan (not even the AC necessarily), a tangy smell like Elmer's School Glue or caulk comes out of the vents. The mechanics at Firestone don't recognize the smell.
Many salon workers face low wages, so tipping is their means of making ends meet. (And on that note, if you suspect your salon has poor conditions for its employees, report it to your local public advocate's office.) Tip 20% for a standard manicure, more if you feel your service was exceptional.
If you get a good pedicure with a really awesome nail technician, you should tip them at least $3 or 20% of the total cost of the pedicure. But you can always tip as much as you want. Seeing someone brighten up because you have tipped them more than they had expected is a wonderful feeling.