Show them a way to invest, very similar to traditional investment instruments. For example, as there are deposits in banking, there are also structured deposits in bitcoin. Thus, it will be easier for them to understand and, perhaps, there will be a desire to invest in bitcoin. Gekkoin is a good example of such a company.
There are different and elderly people, some old people cannot understand simple new technologies, although there is no point in talking about bitcoin to such a category of people at all 
but I like the idea with an example of investment and deposit, to explain to them using the example of what they are familiar with.