What is this stuff in my keyhole?

[WhatTheKey]

I live on a busy main street, front door opens onto the pavement. Lots of pubs around, but I've never had trouble and keep myself to myself.

I fetched my key this morning to go out and fetch the paper, and when I pushed my key into the door to unlock it, this white stuff squished out. Almost sure it isn't glue because it isn't sticky or tacky at all. There is absolutely no trace of this on the street side of the lock iykwim.

Last person to use the door was DS, who came home from work about 10 and locked the door. There's a small trace of this stuff on his key, but nothing like what's on mine (pictured.) I guess it's possible that this white stuff was on his key when he put it into the lock but it doesn't seem likely.

Any ideas? I know that putting glue in a lock is a horrible prank that happens, but don't know of anything like this.

Hand cream? Sniff it.

No smell at all. I thought it might be paint, but it doesn't have that smell.

White lithium grease?

It doesn't look as greasy as that... Almost like Tippex or paint but unscented.

Chewing gum? Does the lock still work?

I've googled and it suggests that someone might have been interfering with the lock. It does look quite old. Perhaps it's time to upgrade the lock and fit a more secure one. They're not particularly difficult to change yourself.

Ectoplasm!

The white stuff will probably be lubricant.

Thanks for this. I can't find anything on google that makes sense... It says glue or expanding foam to mess up the lock, but nothing like this. I wonder if you found anything I didn't?
You're right about getting a new lock, I'll get on to that. Living in the centre of town can get rowdy but there is a sense of false security being here, because it's so busy!

Shame you don't have ring or similar.

i can't think what it could be, but presumably put there by someone up to no good with a spray nozzle like WD40 type can.

weird how DS has 'a little' on his key, but it squeezed out when you put your key in.

Doesn't sound like a drunk plan with DS getting some on his kep at 10pm.

have you got a bolt on the door? If so, I'd be using that until my jitters calmed down!

Just bumping in case anyone's had this happening to them...

I'm sure I heard about this in car door locks?

Yes, there's nothing at all on the street side, which is really weird. There are a lot of us that use the door (2 of the DC, me and DP) but it definitely wasn't used after ten. The odd thing is, the place where we live is so so busy until about midnight on a Saturday night, also lots of cars passing, so if anyone used one of those nozzles to squirt something in, they must be very brazen because they definitely would have been seen by someone! Also, I can't quite see the point- I can't find anything online which says that anything but glue can interfere with a lock by being squirted in. (I do think that car locks are a bit different as PP noted.)