Ray, hopefully they are not too obnoxiously expensive but you might get a direct replacement from sunbeam? Or, you might be able to call them and ask them and they can tell you what the size is, don't tell them why you want to know, ie to avoid their product but ask? Another thing that might work is, Mr. Coffee sells conical filters and other shape filters that are nylon mesh. Some are metal filter, you have to look around. I think they are like 6 or 7 dollars, you might be able to get one of those and just cut a circle out of it the size you need for your pot?
Finally, if it's metal in there already, and maybe even nylon and it's not physically tore up, try ultrasonic cleaning it or even boiling it possibly. You can get that coffee pot cleaning powder, like 5 oz for 5 dollars or get pool pH UP which is the same stuff, Sodium Carbonate, 2 Lbs for like 8 dollars.
When my swiss golds start to get cloggy, I US clean them with hot water and the powder and they work wonderfully afterwards.
Aaron
