I've been keeping two "artificial" scrapes going all year long for several years. I keep the leaves clear as necessary, and don't bother with adding any scent anymore (I have peed in them, added dirt fromother far-distant (fall) scrapes, and experimented with commercial lures in prior years). Deer have adopted both of them - they'll check the licking branches above the scrapes during the spring/summer and keep them open during the fall/winter.
-fsh