The seal is very easy to replace:
With a putty knife - try and pry out the top corner of the gasket and pull straight it out towards yourself. It will be tough getting it started, but once the corner comes out the rest will be easy.
Now replace with new gaskets by pressing the hard part back into the wood crease. Your Home depot store will have the gasket in several different colors and can be bought as a three piece set.
Hope this helps.