I've always removed it.
It's a bear to to read when a full class or module is comments. In the decades I've been working, the only time I've seen code uncommented, or put back in to use successfully, is when it's created and reused in the same part of the same development cycle. Otherwise, it just takes up space.
In the event someone decides to leave code in without comments, and use some conditional to keep it invisible, it better stil have complete unit testing on it to ensure that it doesn't break while it's in retirement. Still, if its functionality becomes useful in the future, it's best to develop it from scratch to the new needs and circumstances.
If code is retired by commenting or conditionals, it's not likely to ever be useful in its current form anyway.
