Thanks for help. I'm not handy at all with a covering iron. I was hoping that this was possible (and easily so) without removing any covering... for example: while holding the aileron straight, hover iron over wrinkles which appear as a result of holding the aileron straight. When the wrinkles shrink, the aileron will hold in the straight position... something like that, but I don't know if it would actually work out that way or if it would just get worse.

But if removing covering is the only way, then I can't do this. I stink at applying covering... tried it a couple of times... terrible.

I guess the picture I attached plays tricks on the eye a little, but it's a noticable amount of deflection right at the tip. The twist is very gradual along the length of aileron. I could try later to get a different angle of it that shows it better.

But I guess I just have to fly it like this and just trim it. It won't handle perfectly I guess. But I suppose I could try now and then the technique that I describe above to straighten it, but very gently trying not to "force a result"... maybe it would work (at least partly) eventually after a few tries.

Cheers