Cleaning exterior ear

Any recommendations on how to clean the exterior tips of my bassets ears? When I first got him (I got him this year, he’s 3 so a mature size) the tips of his long ears were crusty and gross from dipping them into his water bowl and any other substances he chooses to sniff. I use Earth Related ear cleansing wipes and occasionally Vet’s Best Ear Relief wash and dry combo the original owners gave me to clean the inside. I then used the wipes to clean the outside of his ears at the end, where the crusty fur was, and it worked but I did have to scrub hard and it left a foamy residue that I had to clean off after. I work at a doggy day care camp so I bring him with me and he often accidentally dips his ears in pee when he goes to sniff it. I was wondering if there is a better way to clean his ears. Just to clarify, I’m not asking about how to clean inside his ears (though if there are better products than I currently use, I don’t mind hearing about it) I’m asking how to clean the exterior of his ear (the furry part) especially the best way to clean off pee and other gross things.