On an Underwood Touch-Master 5 that I got back in February, there were the remains of spider eggs under the machine. I freaked out when I first saw it because I thought that I had brought a live spider egg into my room and thousands of tiny little spiders would infest the house. Luckily, it was old and not alive, but the damage was still done...

The needle in the typewriter is perfectly explicable.  It was probably being used to pick the typeface when someone dropped it into the mechanism.  That's why it was still pointing downwards !  Mouse nests in typewriters - tell me about it !  I sometimes have to supply fully-working typewriters as film props, usually at very short notice.  This means that I cannot be too fussy about the condition of the machines that I buy in.  A couple of months ago, I had to buy an Imperial 58 that had been nested in by a mouse whilst in storage.  The problem is that mice urinate in their nests, and mouse urine is very corrosive.  Once cleaned out, I had to soak parts of the machine in penetrating oil for a week before I could get any movement at all.  Some linkeages were so badly rusted together that I had to remove them and get them up to a dull red heat to crack the rust in the joints.  I did make the machine type perfectly well in the end, but it was not a job I would want to do again in a hurry !

Freja wrote:

I haven't found anything crazy in any of my typewriters (yet) but one of my typewriters still had a love letter on it. The letter was typed halfway through and never finished. 

Now there's a tragic image.
 

I used a pair of tweezers once a while ago to clean type faces. That was when I didnt know much. Now I use a wooden toothpick or the toothbrush method.

That story about having to heat the parts to get them to move - wow. That's blacksmithing!