DEAR MISS MANNERS: We are expecting guests whose house, when we last visited them, was unclean and had cockroaches. I am worried about them occupying our guest room with their dirty suitcases and such. Is there a gentle, friendly way to let them know we are worried about bugs coming into our home? GENTLE READER: There is no delicate way to raise the subject directly. The best Miss Manners can suggest is that, since the guest room is so small (its actual size is immaterial), you move the suitcases to the garage after they have unpacked. Or take your guests swimming before dinner. *** DEAR MISS …