Reusing Plastic Containers?

So I bring the same thing to work everyday: Turkey sammy, cubers & carrots, and pretzels. I eat in the park so I leave the containers in my car when I return to work. After work I come home and usually give them a quick rinse and reuse them since I am putting the same thing back in. I just read something about toxins releasing when plastic gets hot. Since its sitting in my car at lunch I am thinking I should do way more than give the plastic a simple rinse....or should I bring it back into my office? HELP!