Ruby 1.8 and Marshal.load/Marshal.dump

Where can I get detailed information about now to properly Marshal.dump and Marshal.load objects in Ruby 1.8?
I read in ‘ruby-dev summary 21403-21530’ that instance variables are dumped even if a marshal_dump method is provided for an object and that this is a feature. Why? Additionally, it is wise to make objects Marshalled with Ruby 1.8 unusable with earlier versions of Ruby? The recent changes in Marshal is causing me a few issues.

I need to a way to control what information gets Marshalled for my objects. I could safely do this in Ruby 1.6.8 and can’t seem to do it Ruby 1.8.

Any suggestions is greatly appreciated.

Thanks, Michael Davis