Hi, this is my first post. Brian Briske at Asklouie.com, the 1shot info site is not answering emails. He turned me onto using PET bottles stored upside down w/ 2 − half inch stainless steel nuts to agitate the pearlescent enamels I use. As he's not answering I'm wondering if anyone knows what type of bottle top is best to use… can't find PET tops and am afraid the other plastics will interact w/ the VOCs. Anyone know which type plastic caps I could use? Thanks for any advice.