If you can't get at the reservoir bottle easily use a garden hose spray to flush it all out. Keep flushing until you are sure that all the jellied sludge has all been removed. Be careful not to wet electrical components under the bonnet though.
In future only use prediluted ready-mixed screenwash fluid rather than water in your washer bottle. It's only about £3 for 5 litres from stores like Wilkinsons.
ChicksFan
July 2014