A zipoc bag with tepid (not hot) water. Just move the bag with water inside across your windscreen. Works quickly and no splashing water on yourself when the automatic wipers kick in
If you pour warm water over your windscreen the ice will melt quickly and you can remove any excess slush with an ice scraper. Please DO NOT boil the kettle for this, if the water is too hot it could lead to the glass cracking so stick to warm water from your tap.
A de-icer spray used with an ice scraper is a great solution. You need to use a fair amount and allow the de-icer to work before starting to scrape away.
You can make your own de-icer solution by mixing 1/3 water with 2/3 rubbing alcohol or 2/3 vinegar… or simply buy a de-icing spray at your local petrol station.
Combine an ice scraper with de-icer and you’ll be well on your way.
You should never use anything other than a car-specific scraper as credit cards or sharp objects can scratch your screen.
Keep your gloves handy
Also recommended that you put shopping bags over exterior mirrors – remove bags, perfect rear vision