Using Google, it took me about 7 seconds to find their website and reach the form needed to contact them. It was easy; I just filled in some basic information, and then typed my message. I explained that I'm usually happy with Mission brand tortillas, but that the sticking was frustrating. I was polite and concise.
That was Tuesday. Today, I checked the mail to find that Mission had sent me two coupons for free tortillas, and a brief letter apologizing for the sticking. I also sent an email to Noxzema, explaining that I recently purchased a 4-pack of disposable razors, two of which were broken and unusable; I haven't heard back from them yet.
Whether you're writing with praise or criticism, companies love to hear from you. Just don't complain, don't take advantage, and always be honest. If you've ever written a company and received a positive response back, I'd love to hear about it!