How deep of a cleaning are we talking about?? These bolt actions are pretty simple compared to the semi-auto's. To remove the bolt to clean the bore you just squeeze the trigger while pulling the bolt assembly out the back of the receiver.
I posted a tutorial on taking the bolt assembly apart on the newer T-900 rifles at Rimfire Central, from the schematic at Numrich it appears to be similar to the Glenfield 20 and 25 you have.
The schematic below may help if Numrich has the correct one for the 20 and 25 Glenfield.