I use this technique, which I have succeeded in lifting only one pad out of almost 1000 pads:
1. Apply flux to each side of SMD cap.
2. Heat soldering iron to 400’c with chisel tip
3. Apply heat to one side of cap at solder joint for 5 seconds
4. Apply heat to other side of cap at solder joint for 5 seconds.
5. Repeat for all caps on board.
6. Using a bent needle nose plier, press down on cap and then turn the cap flat against the board from “12 o’clock” to “6 o’clock” then back to 12 and then the other way to 6 and then lightly twist back and forth until cap comes off leaving base and legs.
7. Carefully remove base and twist back and forth any legs protruding so they snap off at the pad / solder.
8. Apply more flux on pads and fresh solder on iron, and lightly but persuasively remove the older solder with the rest of the leg inside and replace with the new solder on your iron. Repeat a couple of times for very difficult to remove legs and pads that look dirty.
9. Clean up with IPA99 and q-tip
10 ready for new caps.