wall paper smell...

idk if anyone knows what i’m talking about, but we just recently redid a room in our house and we had to scrape all the wallpaper off and everything. and there was this awful musty smell. there was black stuff all over the walls that i assume was mold. there was two layers of wall paper. one came off easy and had air bubbles in it that i’m assuming trapped the moisture to cause mold. we made sure the mold didn’t eat through the walls but we scrubbed all the mold off and put drywall putty over it and primer and also painted it. but i can’t get rid of that DANG SMELL. it smelled like musty and old. not even the paint smell took away from it. the only reason i ask is because this room will be a nursery in about 6-7 months and i want the smell to be GONE. i’m pretty sure the mold is gone and that’s not an issue anymore but the smell is gross. please help!!