This is the short version — for when you're already at the dump point.

Empty (in order)

1. Close the blade inside the bathroom.
2. Open the external service door.
3. Unlock cassette → pull out → roll to dump point.
4. Stand upright. Rotate spout up ~90°. Remove cap.
5. Point spout DOWN into dump point.
6. Now press the vent button (not before — that's how splashes happen).
7. Rinse with clean water.
8. Add sanitary additive per product instructions.
9. Refit cap. Return spout to stored position.
10. Slide cassette back in until it locks. Close and lock service door.

Everyday Use

• Open the blade before use.
• Pre-wet the bowl with a quick flush.
• Flush after use.
• Close the blade.
• Travel rule: blade must be closed before towing.

When to Empty

• "Nearly full" indicator triggers at ~80% — only a couple of uses left.
• On slopes or inclines, never go past 3/4 full (vent overflow risk).

Don't Do This

• Don't rotate the spout more than 90°.
• Don't use a high-pressure cleaner inside the cassette (damages the float).
• Don't use chlorine, alcohol, abrasives or polish on the bowl.
• Don't use household antifreeze in the system.
• Don't shake the cassette vigorously.

If It's Smelling

• Empty more often.
• Check the additive dose — too little is the usual culprit.
• Rinse the cassette thoroughly after every empty.

If the Blade Is Sticky

• Clean the seal.
• Lubricate with silicone-based grease or spray only.

Need more detail? Read the full guide: Dometic Cassette Toilet — Full Owner Guide.