Should I use a really old plastic fermenter?

A friend of mine just gave me a plastic primary fermenter that he hasn't used in about 5 years. And even when he did use it, it was only 2-3 times. It doesn't appear to have any deep gouges or anything, but it's quite dirty and has sat in his basement for years.

Is it worth trying to use this fermenter, or should I just suck it up and buy a new one?

You might try a 24 hour oxyclean soak and see how it cleans up, if it looks good after that and doesn't have any scratches then it should be okay. If there's any doubt though, I probably wouldn't risk it - plastic fermenters are not that expensive.

I would just be thorough when you clean and sanitize it. You should be okay - just be gentle when cleaning the initial gunk as to not scratch it in the process.
-Me

The best answer: Buy a new one.

Though admittedly, I have been using an old ale pale that sat in a friends attic for 6+ years. After a few applications of some heavy sanitizers and the occasional nuclear application of high bleach concentrations followed by heavy rinsing, the pail is as good as my carboys. Though, I really only use this pail for non-expensive/experimental batches and the occasional lambic.

Do as you wish, but for starting out it would probably be best to get a new one. They are CHEAP.

I use a bucket for my No wrinse cleaner and keep my tools in it while brewing. I'd use it for that and then use my current cleaner bucket as a new Primary... =)

I have 5 gal buckets around that I'm going to do that with so I have a "Good" Food grade bucket to use as a 2nd Primary.
All in effort to have 2 or 3 brews going at the same time, and that will aide in preventing me from wanting to touch any of the brews daily.

My buckets are all 7-8 years old. I would be tempted to take a hammer and give the pail a few taps on the flanges, just to be certain it hasn't gotten brittle.