If you left the windows and doors open, a few minutes. But its smell won't go away fully until 36 to 48 hours have passed. However, it also depends on the components that go into making the paint thinner. There are four ways you can mask the smell of paint thinner fumes for those 48 hours.  1. Spread a few quartered onions throughout the space to absorb the paint thinner smell. 2. You can scatter freshly ground coffee beans throughout the room in bowls if you have them. 3. It can also be accomplished by scattering cotton balls soaked with peppermint oil or a few drops of vanilla extract around the room. Due to the powerful scents of both vanilla and peppermint, you can also add a few drops to small bowls of water. 4. You can crush wood charcoal before placing in containers and leave them overnight.