I have ads running continually on CL, for my local business. (sewing, knitting, etc.....and teaching classes) Each time I post for a class, or to advertise my business, I include a signature type line at the end.......If you'd like to see some of my work, please visit my Etsy store......and the link.
I guess I don't care about the spam, I just delete it and answer the valid inquiries from potential clients.
I have not put listings in arts & crafts, nor have I listed in any other cities. Will need to try that!