Toyota Repair: Burning Smell, toyota camry, exhaust pipes

Question
When I turn on the AC or after I have been driving the car for a while and get out, I smell something that seems to be "burning". My hubcaps are really black, causing me to think that its my brakes that I smell. I had an oil pan leak before and had that problem fixed about 2 months ago. I haven't had a tuneup and I have 62,000 miles on the car. Any suggestions? By the way, this is a 2001 Toyota Camry 4 cylinder automatic

Answer
There may still be an oil leak dripping on the exhaust system, there could also be something clinging to the exhaust pipes or the catalityc converter, something like a plastic bag that may have been picked up on the road, the high heat of the exhaust fuses it to the pipes, check for this possibility very closely.