Can I add a cosigner if I refinance my loan?

Should I be putting premium gas in my Dodge Charger? I heard that this can make the engine run more efficiently.

I want to get rid of one of my older cars in GTA 5. Is there an easy way to do that within the game, or do I have to delete it in my settings somehow?

My grandmother has reached the age where she no longer feels comfortable driving and decided to give me her car for my 21st birthday. The car runs great and has been sitting in her garage, almost untouched, for the last year or two. While driving it home, I noticed the smell of mildew and found some mold growing on the seats. How can I clean the mold off the vinyl seats?