Housekeeping

I would like to write a script to housekeep large files that are not currently accessed/used and this script is to be put in cron. (These files are actually temporary and will be deleted once processing is complete. However, due to some application problem, the files are not removed, causing filesystem full)

I have the following files with k3file.001 & k4file.001 still processing (in use).

-rw-rw-rw- 1 amark sys 5984 Jan 4 20:03 k1file.001
-rwxrwxrwx 1 amark sys 229 Jan 4 20:04 k2file.001
-rwxrwxrwx 1 amark sys 416 Jan 4 20:08 k3file.001
-rwxrwxrwx 1 amark sys 416 Jan 4 20:08 k4file.001

How do I remove all the files except for k3file.001 & k4file.001? Please help.