The fire that engulfs the Witch's hands as she's trying to remove the ruby slippers is actually apple juice spewing out of the shoes - the film was then sped up to make it look more like fire.

女巫想要拿走红宝石鞋时，手上起的那团火其实是从鞋里泼出的苹果汁，电影用快镜头让它看起来很像火。

youdao

Only four pairs of the ruby slippers are known to exist.

BBC: Wizard of Oz ruby slippers set for UK display

Rhys Thomas, author of The Ruby Slippers of Oz, an expos?? of the Hollywood memorabilia industry, says Shaw's pair was of higher quality than the pair that now resides in the Smithsonian.

FORBES: Swept Up

Pieces of trivia are interspersed between the costumes: did you know that the ruby red slippers worn by Judy Garland in The Wizard of Oz were designed to contrast with the yellow brick road and show off the new wonders of Technicolor?

BBC: Hollywood comes to London��s V&A