The bottom line is that 10% ethanol gasoline is not good for the parts in the Vespa fuel system. Additionally, the use of fuel additives does not seem to be all that effective in neutralizing the effects of ethanol. I have tried both the Lucas fuel additive shown in the video and also the Star Tron enzyme fuel treatment and still got the damaging crud.
The best solution to this problem is to use ethanol free gasoline. It is hard to find but it is available. In the US, locations are listed on the Internet. Usually, the service station will have a special pump for the ethanol free gasoline. With ethanol free gasoline, fuel additives are not needed.
Crud found in sediment chamber above the float bowl.
Ethanol free 90 octane gasoline pump.