Don't know if this go someway to helping you.

But if there are in a set order so for example if the following is in A1

AEFBF23

You could use

=leftb(A1,5) [this will extract the letters]

=rightb(A1,2) [this will extract the numbers]

=mid(A1,3,2) [this will extract, starting at the 3 character, 2 characters. Answer in this case would be BF]

But if there are different lengths you may need some whizzy VBA code

Just thought I would chip in a suggestion