I’m picking up a “new to me” Ys640 this weekend. 
Since it is used, I assume seasoning will not be needed, but what other kind of routine maintenance and upkeep does this unit need?  I believe I read somewhere that some people spray the outside of the cooker with spray oil?

Can anyone give me any tips or info?
Thanks

I sprayed mine once with PAM.  Bad move.  Kinda sticky.  I have hears some use a quality high temp oil like canola and rub it down.  It'll collect dust though.  You can rub it deeper so that's not a problem.  I don't do that, I live in a very dry climate and my 640 is kept under a cover under a porch.  No rust. 

After every cook I clean out the fire pot area with a small vacuum.  Every once and a while I'll scrape the bottom with a PLASTIC scraper (Home Depot) in the paint dept and vacuum the ash up.  Once or twice a year I scrape the full inside well, give it some Simple green and scrub a bit.  I cover the auger area with foil, and ensure the pellet bin and auger area is 100% free of pellets.  I wash the outside at the same time with a green style sink sponge and soap.

The Grates I wipe down after cool down (still warm) with a stainless scrubbing pad like steel wool just to get the chunks off.  I clean the diffuser plate now and then with a metal scraper, usually after every cook. 

I believe I read somewhere that some people spray the outside of the cooker with spray oil?

Can anyone give me any tips or info?
Thanks

When you say "spray oil" are you talking LPS or WD40 spray oil or cooking oil?

I use a LPS or WD40 type oil to clean the outside of my grills. I only do it when cold not after cooking. Used it for years on my ST gas grill before I gave to kids. Outside looked new. I still use it on by GMG DB that is painted about once or more times a year. I just spray some on and wipe off with paper towels. Usually when the wife asks are you going to clean your grill. Again I do this when grill is cold and only on the outside surfaces.

Mudflap

 NOT the outside. The vegetable coating on the" inside" is for a NEW pit to help develop seasoning..Cooking oil on the outside will make a burnt on mess,or some may consider it a well used look.

When I had my YS640 I just cleaned out the inside ever so often. When the unit got very messy I would soak the grates in a degreaser. 

And congrats on the unit. The YS640 is one sweet cooker. I know I loved mine when I had it.

Congrats on your new Yoder. It’s one sweet pellet munchin machine.

I've had mine over a year, all I've done is regularly clean the inside and wipe down the outside. It's not the prettiest smoker in the outside anymore...... Lol

Thanks for the input gang. Sadly, I am not yet in possession of my YS640. On hour three of my four hour drive to pick it up, I was rear ended by another driver. The seller has been gracious enough to hold it for me, and I'm now arranging shipping from uship.com.

This is a lot of work for one smoker, but based on my research it should be well worth it!

Maintenance on mine has been great.  Just remember to clean/vacuum out the firebox before every time you smoke.  I once forgot and left a chunk of ash that clogged the igniter.  Just as well, because I ended up with a half bag of pellets overflowing the firebox.  Gladly they never ignited. 

I think this will turn into a good "remember when" story somewhere down the road.  Hopefully, no one was injured and you'll be smoking in no time.  I certainly love mine.  Everything I've smoked has been way better than anything on my old BGE, which was the best thing I ever sold to upgrade to my Yoder.

I've read some people use Lemon Pledge to kind of polish it up. Any of you all try that?

Six months in on mine, all I have been doing has already been mentioned. Vacuum out the ash and I have scraped the diffuser twice to clean off buildup. Left it uncovered during end of summer under patio awning, now covered under awning just to help with winter conditions but uncovered almost every weekend to use!!! Your gonna love it!