What is allowed in the shows,concerts and whats not? asking experienced people

I'll be seeing MCR next week in Florence!!
However I have a few questions about venues. Right now my main concern is can I wear my spikey bracelets and chockers?
I've also read that venues dont allow bottle caps but allows water bottles? I know that they dont want anyone to throw things at the stage but will my accessories be a problem? Ive been to a few concerts but nothing at this scale before. Im so confusedddd