Smudge of paste on my wallpaper

[StuntPineAppleHead]

I've just noticed a smudge of paste on the front of the wallpaper that was put up about four weeks ago.

It's only noticeable when the light is in the right place. It's a shiny streak.

The wall paper is matte and almost black so the shine is quite obvious.

Is there anything I can do about it? I'm a bit reluctant to go at the paper with any kind of water or detergent obviously.

Is it possible to get a decorator to just cover that one bit or will it be really obvious that the one little patch has been covered?

Thank you for your time.

Try a slice of white bread (without the crust) rolled up into a ball and roll it over the paste mark. It might be too dry to do it now but worth a go

Seriously!?!? I'll give it a go once I actually get some bread in.
It's pretty dry though - rock hard.

I've come across this recommended elsewhere but I'm worried it would strip my paper too.

Anyone else got any recommendations?