Need help! - horse sheath cleaning?

Ok so I own a QH gelding and he needs his sheath cleaned super bad! I know you can do it with his penis inside of the sheath, but is there any way to easily get his penis out of the sheath? I just bought him and I don't think anybody has cleaned him for a few years. please help me get it out!!! I'd prefer not getting a vet out to my barn to do it because he is really mean and he's the only one around.