It’s been several weeks since I last finished one though I have come very close several times.
I figured out the trick quite handily. Add “ch” to the end of a word thereby making a familiar expression wacky. But there were a couple of clues that had me totally stumped until the very end.
8 Down: Currency exchange premium. The answer: agio. I got it by filling in everything around it and knowing all the other answers were correct.
33 Down: Courthouse records. Answer: acta
46 Across: Lead and tin alloy. Answer: terne
They crossed. I hadn’t the faintest idea what the answers were. By filling in everything around them, I was left with one open space, so I guessed and put in the “t.” I was right, and that completed the puzzle.