I need to extract the 21 and 22 from this string to get "2122"

23^^C4~21^^C4~22^^C4

Or it could look like this:

23^^C4~22^^C4

And I would only want "22"

Or this:

23^^C4~21^^C4~22^^C4~27^^C4

In which case I want "212227"

The only truly consistent thing is that there will always be a tilde before the numbers I want.