My partner and I adopted a red-footed tortoise from a less than ideal condition last August (now March). He had been living with two old dogs who would sometimes pee and poop on the floor and he roamed the same indoor space they did so, when we got him, he had the smell of dog urine on his shell. He's had baths and has been happy and healthy since- including putting on weight (he was very underweight when we got him). I got more up-close and personal with him in his bath today and still smelled a bit of that urine smell on his shell. Is there anything I could use to give him a bit of a scrub/rub down with to get the smell out of his shell?