My Zanussi waher-dryer WJS 1397 W works ok, except that significant grit-like deposits gather in the door-seal slots (this can dirty my washing when I remove it) and brown gel-like deposits gather in the filter after each usually lightly soiled wash. I don't think machine's previous owner did any maintenance like clearing filter. I clean out the dirt regularly but it keeps returning. Any idea how I can clear this dirt/deposit problem? Thanks.