When my cat is next to a menthol cigarette she rubs on it. If you lay it on the floor she rolls on it. Why?

we smoke and my oldest cat (who is 3 yrs old) will smell our cigarettes and if it is a menthol she rubs against it. We have laid it on the floor and she plops on top of it and rolls around on it. We can't figure out why she only does this to the menthols.