We use the recommended Thetford Toilet Cleaner (purple label). Need to leave it soak for 24 hours. We also gurneyed inside the unit this time for a "sparkling clean"
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Pay it forward - what goes around comes around
DUNMOWIN is no longer on the road and still DUNMOWIN!
Except for a few litres of water to rinse out I had not cleaned/heavily dosed our cassette for close to three years using "Napisan" only. So recently added a litre of cheapest "White Vinegar" topping up with Hot Water and left sitting for 3 to 4 hours.
Initially the interior walls just had a Crystalline build up which after this application/soaking the inside was a clean as new not a sign of any residue at all.
Also lubricate all Seals/O'Rings with Olive Oil and we have been using the Thetford C200 permanently for 9 years without a problem.
Maybe the OP means how do you clean the outside of the toilet - seat and lid. I know that ours gets marks that are hard to remove from the plastic mouldings, especially more so when in red dirt country. Tried spray and wipe but plastic surface still looks dirty or worn.
Inside we use woollies "boost" (same as napi san) which keeps it clean and smell free. Outside we use a small steam cleaner with spray and wipe. They work well for us and are cheap.
Safe travels
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P B Crockart EX RAAF Electrician,
Aircraft Avionics tech. Senior high school teacher.