Moontamara, we all learn from our mistakes and we all make plenty of them!
I inadvertantly taught one of my cats to wake me up at 3 a.m. for cream and cheese!
My dog knows two commands with regard to not touching things. She knows "OUT" which means open your mouth and drop whatever is in it, and she knows "Leave it" which means don't even pick it up at all.
Get two treats and hold them one in each hand. Put one behind your back. Hold one (open hand) out to your dog and when he moves to grab it, close your fingers on it and say "LEAVE IT!" quite abruptly. Try again with the open hand, repeat. After the second time, he should not even try to take the treat.
When he obeys the Leave It, say "Okay!"(happy voice) then give him the treat you had hidden in your other hand.
I can drop anything on the floor, and my dog will not touch it until I "Okay" it. Very useful and can save your dog from being hurt or poisoned.
I once went into the kitchen to find a foster dog with a very sharp knife, chewing on the handle.
"OUT" came in very handy that day.