Residue glue on face/crystal

[Estiaan]

I got this watch from my girlfriend a couple days ago but it just came back from repairs. The person who repaired it apparently took off the crystal and sealed it using this glue compound. He did a terrible job at cleaning/sealing it neatly and now it has these marks all around the crystal. What can I do about this or can someone please give some more info into why this was done and exactly was done? The watch is in excellent condition except for this residue.

[Ishima]

Glues and cements can usually be rubbed off with a cotton pad and isopropanol (rubbing alcahol) if you don't have something like that to hand, hand sanitizer gel is usually a pretty good and safe stand in for its high alcohol content. 
The repairer should be ashamed though, poor workmanship to get it like that in the first place, shameful practice to call it done and give it back to you like that. I can't tell if the glues only on the outside of the watch, hopefully so.

Edited November 22, 2017 by Ishima

[Estiaan]

My first thought was that this could in no way be correct but I luckily didn't pay for the repair and the watch was not functioning beforehand so I'm not complaining. The residue seems to be on the inside as well and that seems to be the main problem so I will just be saving up and having it cleaned in the near future.

[Chopin]

As has been said, at first glance you can try removing the movement and just try to wipe away the residue with the aforementioned substances on the inside. Even so, I don't think that it will look 100% correct...

Is it glass, sapphire or acrylic crystal ?

Regardless of what it is I'm assuming that the watch uses either a tension ring crystal (unlikely) or a press fit mineral glass or sapphire crystal in which case you're supposed to use a gasket. A watchmaker should have all sorts of these gaskets or at least order the appropriate one.