Hi - I was going to post about this!
Ive been using a mix of olive oil and castor oil on my eyelashes, and Ive definietely noticed a difference! I was using it for about a week before I saw any results though! But yes, using this mix (half and half) did make my lashes thicker and longer.
At the moment, I am using Talika Lipocils, which is a bit more pleasant to use since you dont wake up with oily lids, but to be honest I think the castor oil did more for me and I will be going back to that once this is finished.
So yes, would def recommend!