change old id's(values) with new id's

I had to add a little user-defined function to your workbook to do some of this:

Function LookupReplace(sSourceString As String, rngLookup As Range, lLookUpCol As Long, Optional sDelimiter As String = ",") As String

Dim vValues As Variant
Dim lLoop As Long
Dim vLUResult As Variant

vValues = Split(sSourceString, sDelimiter)

For lLoop = LBound(vValues) To UBound(vValues)
   vLUResult = Application.VLookup(Val(vValues(lLoop)), rngLookup, lLookUpCol, 0)
   If Not IsError(vLUResult) Then
     vValues(lLoop) = vLUResult
   End If
Next lLoop

LookupReplace = Join(vValues, sDelimiter)

End Function

But with that in a module I could use the formula:

=LookupReplace(SUBSTITUTE(TRIM(SUBSTITUTE(Blad2!J2,"#"," "))," ",","),Blad1!$A$2:$B$5,2)

In cell K2 of the results sheet, and just drag it down.

Great!!!! I can't believe you made something so quick!!!

I just tried it and it seems to work. I'm really happy :-)

Since I'm using a dutch version of Excel I had to change the function names in dutch and replace the comma's with semicomma's.
So for other dutch ppl around this the formula in dutch (all credit still goes to Andrew!!!!):

=LookupReplace(SUBSTITUEREN(SPATIES.WISSEN(SUBSTITUEREN(Blad2!J2;"###";","));" ";";");Blad1!$A$2:$B$5;2)

As you can see I also changed the part where you substitute # into a space.
I forgot to say that it was ### that had to be replaced into a comma and not one #. My mistake but was easily fixed by changing it into SUBSTITUEREN(Blad2!J2;"###";",")

Thank you Andrew! You made my day!!!!!!!!!!

Do you think it would be difficult to make it do it automatically with a button so no dragging is needed?
The reason I ask this, is because the sheet has around 4100 rows if I'm not mistaken.

I'm still happy that this works.