Pulling Capacitors From Above

I have resolved that to get my H7874 PSU working better I am going to have to bite the bullet and replace some electrolytic capacitors which cannot be desoldered from below, at least not without some significant surgery on the board (there are components soldered to the underside of the board and attached to a large heatsink, all those components would have to be desoldered so that the heatsink can be removed to get access to the underside of the board). I have had the suggestion to pull the old ones out from above, and then solder in the new ones from above. These are relatively small radial types (330uF, 25V). I am sure the pins will just pull out of the bodies of the capacitors, leaving me to desolder the pins from above, which should be OK. But, I am worried about doing damage to the board by just pulling them "cold". Are they really just going to pull out of the capacitor body, or does anyone have any tips for doing this in the least damaging way possible? Thanks Rob