Extracting just the numbers works well, but since you describe a problem with getting blank stuff you don't want, you might as well know about grep ...

22 11:56:12 tomdlux [ ~ ]
$ p522 -E 'say for split /\D+/, "MD:Z:4C3C7C0T2^T9C44"'               
+    

4
3
7
0
2
9
44
23 11:56:19 tomdlux [ ~ ]
$ p522 -E 'say for grep {length $_} split /\D+/, "MD:Z:4C3C7C0T2^T9C44
+"'  
4
3
7
0
2
9
44
[download]