I'm looking for a program, perhaps something like ImageOptim, that can either completely clear or edit Metadata from PDF files.
I'm using OS X Yosemite 10.10.4.
Thank you!
It really depends on the ultimate goal you're trying to accomplish, the level of security you need, and the line of work you are in.
If you are working sensitive files / confidential files / client documents, I would only recommend using a Pro version of Acrobat, especially if you intend to send these documents to a third party (perhaps a court, an arbitrator, government agency, IRS, etc.) or an opposing party (lawyers from an opposing party, etc). In both of those instances, the stakes are high, and accidentally revealing metadata could prove to be extremely damaging.
Acrobat makes the process easy, and is customizable - you can select the types of metadata you want scrubbed, etc. It's also the most secure. I'd also recommend Acrobat if you need to deal with preserving documents in archive formats (PDF/A). Acrobat Pro is the standard in the legal community for dealing with PDF related tasks, no question.
But if you're just looking to scrub for internal use or non-adversarial parties, then I'm sure you could use something less secure, but I am not aware of another program that can accomplish this. Certainly Acrobat isn't cheap.....