What's the Name of That Book??? discussion

SPOILER:
At one point the boy is in a truck with some nitroglycerin and puts it in water to cushion it and keep it from exploding. He also uses baking soda and vinegar to blow out a candle to escape at one point. He may have (if I'm not mixing up my books) bought a Guy Fawkes effigy at one point and the book may have contained the phrase "A penny for the Guy" I've searched every which way and cannot come up with the title, which may have contained a lot of E words - extraordinary, egg, enormous all come to mind. I also remember that the cover didn't seem to be all that connected to what actually happened in the book.
Thanks in advance!

I found The Case of the Silver Egg by Desmond Skirrow and the plot sounds right. The cover doesn't match what I remember at all and doesn't look familiar. I've ordered a copy to be sure. Will update when I know this is solved.

Kirkus Reviews description of The Case of the Silver Egg by Skirrow. Desmond.:

- "If you have a go at this one, you'll have your quidsworth--an adventure, espresso, boffo also with lots of 'umor, entailing the doings of the Queen Street Boys and Mino-Minor in particular, whose father, a nuclear scientist, disappears. So does his Silver Egg (the ""smallest and most powerful source of industrial energy ever discovered""--except maybe for Mino-Minor whose ergs seem to be limitless) in the hands of the enemy, one Schpittz who is described as having a slight accent. ""Vott it izz this der meanink of"" (and how did dis ""this"" get in there?)..."

There are different cover images.

Solved! The book does seem to be The Case of the Silver Egg, but none of the covers I can find for it are what I remember. I do remember that the cover in my library never seemed to match the book itself, but I liked the book anyway. Or maybe I'm not remembering the cover correctly - mashing up two different books into one? In any case, this is the plot and details of the book I was thinking of. Thank you for your help!

Great! Glad you found your book, Cindy.

Looks like there are at least two different covers: .