If you do this, make sure to use a control cleaner, not a contact cleaner like Deoxit D5. Control cleaner also lubricates and is safe for pots and encoders. Contact cleaner doesn’t lubricate, and will actually wash the existing lubrication out of your pots/encoders, which can make them feel bad, wear faster, or if you’re unlucky completely seize up and stop turning (that last one’s not so likely with encoders).
This is the best way to clean an encoder but it’s also a lot more work and a bit risky (but still much easier than replacing them):
If you open it, you can use a contact cleaner to clean it and then reapply a suitable oil (I use Deoxit D5 for cleaning and Deoxit FaderLube for re-lubricating)