Make sure you use the best rinse aid and plenty of it. The dirt stuck to the cups and mugs on the top shelf is just small particles of broken down food debris baked on hard during the drying process. Rinse Aid breaks down the surface tension of the water droplets allowing them to drain off before the drying process begins.
Use salt and a decent detergent - avoid the Multi-Tab products - if they were any good, machine manufacturers would not bother with Rinse Aid or Salt chambers.
You might also buy some cleaning tablets and run the machine with these in now and again - it worked for me.
Check the jet holes of the rotating arms - they sometimes get blocked with Jam Pot labels - clean the filters.
Good luck...
Peccavi, July 2009
