Very old/ugly/nasty basement floor. What can I do with this? (pic)

[Emily Knowles]

Here is a picture of a 80 year old home I looked at today. http://imgur.com/tWsmECT

You can see it is uneven, rough, ugly. The black is adhesive left from them prying up the asbestos tiles. What in the world can I do with this floor to make it more appealing to a tenant?

Simplest: paint it. But I'm not sure if paint will even stick due to dusty gravelly surface. 

Expensive and may not be worth it: Level it with self-leveling compound.