Although washable hoses are nice, I can undersand the use of non-washable. There are some very nice leather hoses out there. If you hose has 1 major "flavor" to it, assign only that flavor to smoke through it and purchase a new hose. I have 2 Nammors, 1 MYA (supposedly washable) and 2 Syrians. The Mya is general use, but the Syrians only get MINT flavors run thru them as they aren't washable.
If worse comes worse, remove the end tips and puchase some tubing, see the How-to section (http://www.hookahpro.com/forum/index.php?topic=337.0
) and modify your hose till you can purchase a new one.
PS: if you do try running a liquid through your non-washable, use warm lemon juice and blow dry like rayver said.