I've taken probably a dozen or more rolls of E-6 and a few K64 to my local Walmart. I use a black sharpie pen and cross out all the options on the envelope and write boldly "SEND OUT - SLIDES" or something like that at the bottom. So far the only problem I have had is that one of my rolls got returned to a different store, but they corrected that in a couple of days and no charge. The store I use hasn't much of a clue about slides and they usually think that the order was done wrong since there are no prints. I usually have to explain it's just fine, it's exactly what I ordered. For the longest time didn't have the right charge on E-6 120 and were only charging me $1.36/roll, which I tell them that it should be more like $4.88, (even $4.88 is a good deal and I'd hate to have them shut their E-6 service down for not making enough coin). Anyway, all the slides I've gotten back from them thru a Fuji lab or Dwaynes have been very clean with good colors, which is more than I could say for the local so called pro lab which usually provided lots of crud and scratches at no extra charge (actually a lot of extra charge). The other slick thing is being able to call an automated number to check status of my order using the envelope number, usually it's about 5-7 days.