Why do my car windows streak right after I clean them?

Streaks usually come from residue rather than dirt: too much glass cleaner, a towel that is dirty, saturated or washed with fabric softener, cleaning warm glass in the sun, or an old rain repellent or interior film being smeared around. Use a small amount of an ammonia-free glass cleaner, a clean waffle-weave or glass-specific microfiber towel, and a second dry towel to buff. Clean in the shade on cool glass. If streaks persist, the glass may need a deeper clean or a glass polish to remove old coatings.