cleaning valves and internals?

[cals400ex]

i was just wondering if i was able to clean my valves and other internals since i have the bike apart and i am in the process of installing a piston and cam. what cleaners are safe to use. i don't want anything that will ruin the seals and such.

[UglyMotha™]

spray carb cleaner works good or kerosene and a brush

[300exOH]

No smoking!!!

But seriously you can also use brake cleaner or even WD-40