Removing Deed Restrictions

We bought a house a couple of years ago that had deed restrictions with it.  The house is in PA, sigle family with 10 acres of land.  At the time of purchase we didn't think much about the restrictions because they were things that really didn't concern us personally.  However, we have decided to sell and have found that the restrictions are really inhibiting the process.  What do we need to do to try and get these restrictions removed?

What is the nature of the restrictiobn---for example my deed has a restriction about not cutting down a tree--long since dead!

But a restriction to not build a home over 24' high might be valid forever!