In my (limited) experience, DX4 heads are too fragile to be successfully reclaimed. Is the print head old? Or did it sit too long without use/maintenance? An old (high shot count) print head will not likely be recoverable by any means. If there is ink that's dried inside the head, it can theoretically be dissolved with solvent and time. I have reclaimed one head by simply soaking it in a bath of cleaning fluid and using a syringe to pull solvent backwards through the head and out the manifold. It didn't print well, but it certainly could be called some degree of recovery. I did it more for the challenge rather than to use it afterwards. If you've got the time to spare, it could at least be a fun, educational experiment.
I have sent back a couple of print heads to a vendor to have them ultrasonically cleaned, but both times the results were negative.
Good Luck