Bottle Capacitors

[Irrelative-at-aol-dot-com (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

I'm making bottle capacitors out of Snapple bottles but I have a quick 
question.  Snapple bottle caps are made of metal - will using them affect the 
capacitence or somehow make them not work?  I've read that you should find 
plastic caps, but I just want to know if it will make a difference cause 
finding something made of plastic to cap a snapple bottle is gonna take a bit 
of work.  Thanks in advance!    --Justin