They can look really scabby and kinda oily but I never cleaned mine until it was time to post. Most of the "ick" was left over residue from tape residue when she had her ears up in her cup. That got cleaned up when it was time to post so not really a big deal to just let them be to air dry and heal. As long as they don't smell or are oozing anything. You can gently clean the inside of the ears with soapy slightly damp warm paper towel. Definitely NO hydrogen peroxide and no antibiotic gel as it can do more harm than good.
Throughout posting I used Chlorhexidine antispetic wipes for ear wax and any sores. Worked fantastic at keeping the ears clean and healing any red spots!