The answer on Dualit's web site to the question "How do I clean my classic toaster" is as follows :-
"With a damp cloth. Stainless steel cleaner can be used on the central cover only. It should not be used on the ends as this would cause discolouration. Instead we recommend that you clean the end castings with a damp cloth and then use a soft dry cloth to polish them afterwards."
But what people find is that the aluminium end castings oxidise (go dull) and dark spots form on the surface. They are difficult or impossible to remove with a damp microfibre cloth as are the burn marks on the stainless steel cover.
Vistal Multi Surface Cleaner removes the burn marks, oxidisation, grease and spots from aluminium AND stainless steel parts in one go. It's an easy and effective way of restoring Dualit toasters to pristine condition and at the same time it leaves a protective, even, streak-free shine.