Ah F*ck!

You'll run into trouble if it's emulsion, as you'll re-emulsify and the paint will come off / mix with the grease. If it's vinyl, you should be ok with some of the serious suggestions... It's probably emulsion, though.

So why don't you paint over it, as suggested? I would guess it's "magnolia" - all landlords love the stuff.

PS I have the same problem with tyres when I lean bikes against walls.

Magnolia tyres? Pics please!