Never could clean a carto and make it new. I use'm and pitch'm. Cartos are cheap.
I clean my cartos about once a fortnight. Some have maybe 15ml of liquid through them between cleans.
I shove them up
Inside the tap and flush lukewarm water through them and pop them into a pot of boiling water for about 20 mins.
I let them cool and blow as much water as I can out of them and then dry them in the oven for no more than an hour at about 130 C (or 45 mins at 150 C) and then turn the oven off and let them stay in there as the oven cools.
I might lose one here or there but they last me so long the labels are wearing off but they're still going strong.
I find vertical coils a little more forgiving than horizontal coil cartos.
15 Boges can generally be had for $20.00 delivered .. that's $1.33 each .. I'm getting a minimum of 5 days per carto .. or about 27 cents a day cost .. don't see any compelling reason to attempt to clean for me, anyway ..
I am however, saving my uncleaned / used cartos in a can .. just in case the Apocalypse scenario is real ..
+1 Willie. I just bought several hunded from Health Cabin for $.68 each. Why on god's green earth would I bother to try to clean/re-use them.
To me, it's like trying to re-use an oil filter.