Hi Cheryl and welcome to the GMB.
While I don't collect the clowns, I have sold a few in the past and have pondered the scorpion marks before. In fact Iwas in touch with someone who reckoned these were an indication of a 'true' Murano make and was actually researching this very point.
They would appear to be a crease made in the glass while being formed, or cooled and the so-called Chinese copies (should they be called 'fakes'?*) were never supposed to exhibit these. Certainly the ones without these marks always appeared to be made with a much brighter glass and therefore looked newer.
Labels are the obvious pointers and you will come across these very occasionally, but these will tell you one way or another. I actually had a 'Womble' clown with label that indicated it was Venetian but, as can be found elsewhere on the board, this does not necessarily indicate it is Muranese, Venetian ,or even Italian! I have a photo of this somewhere and will post it shortly.
I believe Paul (chuggy) has had a few in his time and may be able to offer far more insight than my stumblings :wink:
Certainly worth pursuing though, so perhaps you might like to make a study of it?
* I'd call anything 'a fake' where the intention was to deliberately mislead or falsify. However, 'copies' are the sincerest form of flattery in some people's books :wink: