the energy in the capacitor has a certain voltage which will be delivered. The energy might be gigantic, but if the voltage is small, the current will be small as well - proportional to the resistance of the load. The oscilloscope itself has large input resistance, so if the voltage is small, the current will not harm the input. At 10x probe set you can probably measure directly the 220VAC (with mine this is possible), and the energy in the power lines compared to the capacitor is like the sea and a water-drop. No worries (again IF the voltage is small).
PS: I'm about to announce the openning of a new section in the site, in which everyone will be able to upload the worklog and present their project. Right now it is in the final stages of the Beta testing (the editor). Some people are testing with me the editor - you might have seen new posts from other people instead of me in the site. If you want to start a worklog page in my site, i can make you a beta account and start posting the worklog of this project.