Spam from Moniker Privacy Services.

I'm getting a bunch spam from Moniker Privacy Services & other domain privacy services but they seem host their smtp servers everywhere in the world (mostly in the US) and below are some examples of what I got when I did a whois on the some of the domains:

a-trigano.com
66.197.198.131
OrgName: Network Operations Center Inc.
OrgId:          NOC
Address:        PO Box 591
City:           Scranton
StateProv:      PA
PostalCode:     18501-0591
Country:        US

irjaws.com
74.199.140.202
OrgName: Metroglobe
OrgId: METRO-339
Address: 3675 S Rainbow Blvd
Address: 107-181
City: Las Vegas
StateProv: NV
PostalCode: 89103
Country: US

But these domains (and many more) are registered to:

Moniker Privacy Services
20 SW 27th Ave. Suite 201
Pompano Beach FL 33069
US

I'm checking if anyone else seen this and has anyone able to stop this tspam from these domains hiding behind (or they just a front for) these domain privacy services for spammers. The spam scores for some of this spam are just below my spam score threshold so they are slipping through.

Thank you,
Frank