Smoked and painted on graffiti is also a cleanup problem with its pros and cons. Prehistoric cave art or authentic signatures of famous people may have value. Signing a cave as evidence of exploration or visit was acceptable up to the the 1950's and important data can be found from examination of such things. As a rule, graffiti should only be removed after photographs are taken of anything deemed possibly significant, and after consulting with the landowner and someone knowledgeable about the history of the cave. Youth groups have removed 10,000 year old rock art, and signatures of American presidents have vanished after enthusiastic cleanup trips.
Restoration is slightly different from cleanup.
Just eliminating human interference won't do. Restoration is the effort to put things back the way they were before they were damaged by people. Gluing and reattaching cave deposits, carefully removing concrete or artificial structures designed to be permanent, smoothing mud banks, cleaning mud from speleothems, and restoring natural water flow are among some of the aspects of cave restoration. Paint thinner may be the most effective way to get off spraypaint, for example, but using thinner can be harmful to cave life, and is not recommended. Some cleanup and restoration efforts don't take place in the cave at all.