Childrens fun book- Boy and a modern witch

Can anyone help me find a book which my Dad used to read me 20 years ago? It involved a young boy meeting a modern witch who flew on a vacuum cleaner. Somehow or the other, the witch got shrunk to less than 2 inches. The boy then had to collect many different object to make a spell to bring her to the normal size. I remember that the boy had to collect a few white hairs, and he smuggled the tiny witch in his pocket to school to get hair from the teachers head. They also had to recite the Gettysburg Address while the pot was brewing to complete the spell.

Thanks

The Wednesday Witch by Ruth Chew. Good story!

Hey that was real quick, Im impressed.. Thank you