Ha! I just cleaned some of that a couple weeks ago. Hadn't been cleaned in about 15 years, came out great though. A week later he decided it was time for new carpet and tore it all out! Guy is 89 years old, put that carpet in new himself, he thinks it was the early 70's, tore it out and installed the new carpet himself. I hope I'm still able to work like that at 89!
Its funny reading this thread, reading how carpet has changed. Seems like its gotten less durable, and harder to clean. Disposable like most every thing else now days.