[{"_id":NumberLong(2761632),"data":{"field.with.dots":{}}},{"_id":NumberLong(2761633),"test":{"a":"a","b":"b","c":"c","v0.0.1":"ok"}}]

db.collection.update({"test":{$exists:true}},{$unset:{"test.a":1,"test.b":1,"test.v0.0.1":1}})