Extract from the RAC website - https://www.rac.co.uk/drive/advice/winter-driving/how-to-demist-your-windscreen-in-double-quick-time/?utm_source=email&utm_medium=email&utm_campaign=CHUB_MEMSIN_B_W12017-11-02_130020_7825620&cid=eml-email-CHUB_MEMSIN_B_W12017-11-02_130020_7825620-Drive_NL_MEMB_1st_Feature