"excuse me but you stink & need a shower"
lol, now i would imagine the person being horrified and definitely offended.
Actually, my dad dropped into my brother's place once on his way home from a mountainbike tour to see his grandson. The next Sunday at dinner, my SIL announced that she would prefer if he went home to have a shower first.
Let's just say, he didn't go there for quite some time...
by the way, he's one of those lucky people who don't really get bo. He has bad breath instead...

Sasa