Hi Margaret,
I have just cleaned out the bit you are describing. In respect of the part you may like to look at the following web sites - the item seems the same as mine.
http://www.ersatzteilonlineshop24.de/Regenerierdosierung~-8946301.html
and article No. 260017 seems like mine too at http://www.hgt24.de/shop/luftfallen-regenerierdosierungen-neff-c-90_111_13576.html?osCsid=ht7a8m0f4saij7mi6gtna3khq7
Hope this helps.
Wayne
September 2009