Xslt 2 stripping out non-numbers

Greetings,

I need to strip out non-numerical values from a string.  

Here is a sample input value:  TUV0062

And what I want is :  0062  (or just 62)

Here's what I've tried so far:

for $i in tokenize(state_license_number, '\.') return xs:string( if
(string(number(.)) = 'NaN') then '' else $i)

But this does not work.  I get an empty string as a result

If I do this:

for $i in tokenize(state_license_number, '\.') return xs:string($i)

I get the whole string back so I know my "for" statement is returning
something.

What is the correct way to do this using XSLT 2?

Thanks,
Jim