Yesterday I went to the National Archives in Waltham to look up some Naturalizations. Walter Hickey (a great guy and lecturer) gave me this valuable tip which I'm passing on to you. Some of us irish researchers have family names that are common - Shea, O'Connor, Kelly , Murphy etc. so it's sometimes very difficult to find their records. This is what we should do....go to the Registrar of Voters in the town or city! Ask to see the voter registration for (example) Patrick Kelly who lived at 158 Bridge Street in Worcester in 1900. If he was foreign born he would have needed to show his naturalization papers in order to be a registered voter. The Registrar would have written down what court and reference data from this. With this info it's much easier to go or email the archives and get exactly what you need. I hope someone will try this in Worcester and report back.
Also I overheard Walter tell someone that citizenship of the father through naturalization was passed on to his minor aged children (this was true up to 1940) so that some of us looking for naturalizations of kids in a family that emigrated from Ireland will not be found. (!)