Since we have a few kirbys from when my brother sold them about 3 years ago, I checked out the dirty cup feature as they really are a great vacuum... WAAAAAYYYY over priced.. but great vacuum none the less. All be it the manufacturer had a lot of bad reviews against it. Apparently once the in canister filter clogged up the canister, the vacuum would loose airflow and thus suction. Also the canister severely limited the the air flow even when clean, diminishing the performance fo the vacuum. A company like Kirby with a million and one attachments would surely have brought out a canister attachment for the vacuum if they thought it worthwhile.