I use warm tap water. The majority of the time, that's about all it needs. Some will say only use distilled water, but I haven't had any problems and cleaning under a gently running tap is so much easier. When more is needed, the completely disassemblable (not sure if that's a word) design of the 580 is great. Many will clean it with pen flush, whether store bought or homemade (you can find plenty of recipes online). But being able to open up the pen and get in there with a cotton swab is convenient. When Sailor Yama-dori left a bit of blue-green residue behind in my 580, I actually wiped out the body with a disposable eye glass wipe and it came right off.