Zorst pipes cleanout - options?

[jools]

After my flooding issues I'm left with very oily, smokey exhaust pipes ('cigar' type -'84 RZ250).
I guess I'll start swilling with petrol or kerosine, then maybe degreaser and car pressure-wash? I suppose I may have to burn them out, make a bonfire!? Anyone have any idea of the internal structure? Obviously there'll be a former to support the front end of the baffle, anything else in there? (with ref to getting burnt carbon out afterwards).
Nasty job! Any tips would be helpful.

[hybrid]

Throw some nuts and bolts in there to help loosen any carbon too.
Caustic soda (draino) works well, but you have to be VERY careful with it... plenty of safety gear on.

[JonW]

There are lots of baffle plates in an OEM pipe of that vintage, I would use caustic soda (oven cleaner etc)... double up on the saftey gear!

[L.B.]

Or find your local radiator repairer or heavy diesel engine wkshop if you dont want to muck about with the chemicals.Get them to acid tank the pipes,just did my DG's this way.

[BRG1200]

That sounds like a tip I wouldn't have thought of

[jools]

Cook-up (cock-up?)
Job done