I'm playing the 1.5 update of Stardew Valley, but I'm continuing an old save file where I already finished the Community Center bundles. So buying an auto-petter from Joja-Mart isn't an option anymore. I've seen I can get them as a reward from Skull Cavern treasure rooms though.
So far, I've been digging for about a year, with no success. If I have a very lucky day, I ignore harvesting and animal husbandry and use the warp totem to spend my whole day mining (while having eaten some spicy eel for extra luck and speed). On such days, I can get 0-5 treasure rooms (the 5 only happened once). If my days aren't extraordinarily lucky, I do my chores and basically spend the afternoon and evening mining, getting anywhere between 0-2 treasure rooms.
I've gotten a lot of stuff from the treasure rooms, but it seems to always be the same: dark cowboy hats, (mega) bombs, sprinklers, and cactus seeds. With very occasionally a seed maker or crystalarium. Looking at the wiki the chance of getting an auto-petter should be about the same as getting all this other stuff, but even so I'm getting massive amounts of bombs and hats, and almost nothing of the other 1/25 chance stuff. This makes me think I'm doing things wrong.
Seeing as I need at least 2 auto-petters, and preferably would like 4 of them, are there any tricks I can use to acquire them faster? (I don't mind if that means 'cheating').