I am re-texturing the Poser 5 male double-breasted jacket. The original is a crocodile texture which is, well, not very classy. So I made a brown, grey and navy version and they look fine except for this one green polygon on the lapel. tried a procedural texture, and it is still there. I removed all textures and it stays. Looking closely, it is even there using the original texture. What is going on?

Maybe is a polygon with inverted normals?

The green polygon seems to belong to the "Preview" material, rather than "Collar".  You can apply your new texture to Preview or use the Grouping Tool to change the material for the problem polygon.

A quick look at the OBJ file in Amapi shows LOTS of misgrouped polygons.  If you're going to sell this, you may want to do a complete remap.

I was planning to give it away as a freebie, but you are right Ockham, the mapping is not very good at all. Perhaps I should give it a remap. One of the textures I tried to apply was a pinstriped material and those stripes went all over the place.

Incidentally, I'm glad to see more stuff for Don and Judy.  The P5 figures are
the best answer to the question in the thread below, about what we'd do if Daz
disconnects from Poser!

 While i don't agree 100% with Ockham (because Simon s my all time favorite Poser character!) - the native Poser people deserves a lot more TLC! they're not as bad as the Daz-centric peeps will have them be!

Some of them have issues, yes.. Judy's face...  ICK... but she has a VERY nice and natural body! and Don isn't half bad either... 

So YAY to anone supporting the native Poser figs.

Back, before the Daz-reign, people were actually SUPPORTING Posette and Dork. And yeah I know.. because that was all there was.. but LOOK at some of the STUFF that were made for them.. some of is STILL unmatched!

Don't diss Poser figures JUST because they're Poser figures :)

Quote - I am re-texturing the Poser 5 male double-breasted jacket. The original is a crocodile texture which is, well, not very classy. So I made a brown, grey and navy version and they look fine except for this one green polygon on the lapel. tried a procedural texture, and it is still there. I removed all textures and it stays. Looking closely, it is even there using the original texture. What is going on?

That is a separate piece of the model.  Just a single polygon.  And its normal is flipped.  Who made this jacket?  Terrible.  Well, back in 2002 no one cared about these things.

Go into the group editor and select the group that has the crocktexture applied to it and "Add Material">Preview and it will grab all the polygons left in the Preview material and add them to the Jacket material. Then just Reassign the Jacket material back to the edited group.