Strange request. No, really. It's about flies.

[pronker]

I chatted with another LJer some years ago and she lives in northern Italy, Tuscany as I recall.  Anyway, there's a custom among the region's restaurants to hang baggies of water in the kitchen to ward off flies and the baggies have a number written on them?  Like 13 or 42 or 69 or something?  It's, er, bugging me.  It seems she showed me a YouTube video about it ... thanks for any help.

FOUND not YouTube but photos, not on baggies but posted in kitchens.  The secret number is 58.