You could do it that way, but you can save confusion by writting it in it's appropiate key. If you don't, you'll end up with alot of accidentals and it might confuse you. If you write a guitar part in C major, you would write the clarinet in Bb major. If your just jamming with someone on clarinet, you can either tell him to play in Concert pitch (i.e. Say you play a C major chord, you can tell him/her to play a Concert C. If he understands, he'll know to play a Bb on his part, then all will be good.) If they don't understand Concert pitch (which I doubt), you can just tell him/her to play a Major second lower than you (Bb over your C).
"My whole life is a dark room...ONE BIG DARK ROOM" - a.f.i.
