I did an oil extraction on my old DZ as well as a complete resurfacing. I tried to
get it close to its original condition. When it was new, I used it off and on for the better part of a season and then moved on to newer releases. However the primary reason
it does not perform as it once did is due to the fact that the lane oils of today are being applied with more volume than in those days. In addition, the oils of today are in general, slicker than they were 20 years ago, so I never expected it to perform as well as it once did. I also have an 18 year old Columbia Pulse that also was a great performer18 years ago, but it's simply not, on today's conditions-- again, no big surprise, and for all of the same reasons as the old DZ. That's why i caution my students who search for a ball that performed well for them years ago. They should not be disappointed if it does not perform as it once did on the conditions it was once
designed for.