Looks like small holes to me:
http://catalog.worldpac.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1Y70MFKNH22J0UIDVT&year=1983&make=MB&model=300-DT-001&category=D&part=Diesel+Prechamber

You need to pull them out anyway.Not just the broken ones either, all of them. Then I would imagine it would be easy to rig something up to vacuum out the cylinders.

Danny

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1984 300SD Turbo Diesel 150,000 miles

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