Dispose methods can be called automatically, if client 
forget to call it.
for this ,Call the Dispose method in Finalize method and in 
Dispose method suppress the finalize
method using GC.SuppressFinalize. Below is the sample code 
of the pattern. This is the
best way we do clean our unallocated resources and yes not 
to forget we do not get the hit
of running the Garbage collector twice.

Public Class ClsTesting
    Implements IDisposable
Public Overloads Sub Dispose()Implements IDisposable.Dispose
' write ytour clean up code here
GC.SuppressFinalize(Me)
End Sub

Protected Overrides Sub Finalize()
Dispose()
End Sub
End Class