Black Powder in a SP Rifle

[MtnMike2]

I have a 45-70 lever gun in which I shoot smokeless powder cartridges. I'm considering shooting some black powder cartridges but it dawned on me that black powder has different cleaning fluids. Do you think it could hurt the rifle to shoot the black powder cartridges, then clean thoroughly before shooting smokeless again? I intend to use smokeless for almost everything (target and hunting). The black powder is just for fun - shooting steel.

Thanks,
Mike