Why you delete my other posts? Do you want me to put this cheat here?! I don't usually have bad intentions, even if I know there's a bunch of idiots on the other side. Ok then...
1. Load puzzle.
2. Use "hint" and "move" button to see what move you must do.
3. Reload puzzle page in the browser.
4. Make the move you see above.
5. If there are more moves, use "hint" and "move" and reloading page in the browser again.
You can make around 100 score points on 5 minutes, 1200 score point on hour, or around 65000 for 50 hours without even need to solve the puzzles.
So what will happened if someone canceled puzzle and close the chess.com site? Next time if he/she loading puzzle page again, canceled puzzle is loaded too. This mean that he can solve the puzzle in mind several minutes, next to close the page, opened it again and solve it for 5-10 seconds. In this way he will make maximum points on it. If you want to use time as factor for puzzles score, when page is closed the player must get negative score, no matter what is the reason for this, and next time he/she opened the puzzle page, the loaded puzzle must be new one - so you to deal with this type of exploit.
P.s. Puzzle score must be determined mainly on players PASS RATE, because now it is absurd 1700 rated Puzzles to have past rate over 60 %, but some 1200 only 30% pass rate. You have enough data of pass rates already, so to zeroed liderboard and players scores and start again. 3000 rating on puzzles with under 10 % pass rate is good enough. If you feel uncomfortable to zeroed the fake players scores, simply introduce new additional score named Pass Rate Score (PRS) for the puzzles. The chess is full with low self-esteem people don't give them opportunity to shine with fake endeavors - it is good idea even to remove leaderbord for puzzles and leave only new one PRS for people personal use if they want to see where they realy are. Do you see ELO is determined by wins and loses, the Puzzles score must be the same, and PRS is the most objective score you can get. Do you understand this?! You must remove even the hints of the puzzles if you ask me, and the correlation between ELO and PRS will be seen immediately for peoples that don't cheating on puzzles.