Tamiya Extra Thin Cement comes with a very nice brush which allows more control over how much cement you are using. You can also use a cheap and tiny paint brush. Needless to say the brush now will become a "cement only" brush and useless for painting. By any chance are you using Tenax cement?

If you get too much cement on anything don't bother trying to wipe it off. It will just get worse. Wait till it dries completely and then sand or scrape it off.