Without giving too much away, the way I solve these puzzles is to first solve one row, and from there, solve the rest of the puzzle. While some might feel that the selection of the first row is random luck, I have a process that usually results in the proper first row’s being selected about half the time.
The issue I am having is with Extreme puzzle 18. I have tried each row as the first row, but am unable to solve this puzzle. I have double checked my efforts and have not made any stupid mistakes. My (initial) questions are simply these:
1: Have you found a solution to this puzzle?
2: If you have found a solution, and if you use a process similar to mine for solving the puzzle, which is the first row that worked? (My best results, i.e., the most items removed, were with row 3 and row 5 as the first rows.)