Could I ship this without boxing?

Plastic side skirt piece I'm offering up for sale. Paint is trashed and I don't care about it. Can I just slap a label in this ans send it? Or would bubble and plastic wrap be the bare minimum? 

You can ship it like that. You can slap a label on a potato a d ship it. I would ask the buyer of he/she has a problem with it. 
and of course the shipping company will tell you they won't cover any damage, but that's not really an issue here. 

Summitt shipped my roll bar in a plastic tube a bit thicker than saran wrap.

You have some pointy looking bits on the ends.  I would bubble wrap that end and secure the bubble wrap with tape.  Just a few inches up would do it.

Thanks everyone. Good "point" about the ends. 

Just bubble wrap and tape it. 

I received an exhaust manifold from Latvia that was packaged in a taped-up garbage bag with pieces of cardboard inside on the pokey bits.  It got here just fine.

I shipped a neon bumper that way 

I shipped wheels with UPS once that were not in a standard box.  UPS charged me a lot more to ship them because the wheels would not be able to ride the conveyor belt.

noddaz said:

I shipped wheels with UPS once that were not in a standard box.  UPS charged me a lot more to ship them because the wheels would not be able to ride the conveyor belt.

This is a thing. Unboxed items have a surcharge. It used to be $10. No clue what it is now. 

UPS/FedEx will take it, but I don't think USPS will. 

Depends... what shape do you want it to be when it arrives?

Fedex has a three sided long box for express shipments (we just put our label over the word "express").  I used to ship axle assemblies in them.  Best part - the boxes are free.

+1 for the 3 sided box

Can't find the picture, but I got a tailpipe / muffler from Rock Auto that was completely unpackaged - just a mailing label stuck on it.