Door lock barrel ?

[belfastmark]

Hi All !
Recently, I had someone remove the barrel on my drivers door, MK4 4 Door Golf 2001.
When removed he cleaned what looked like gunge/oily stuff from it and popped it back in.
That was about 2 or 3 weeks ago.
Now, when the key is in the barrel, it seems to stick a bit when opening and closing.
I am now thinking that the gunge/oily stuff actually served a purpose in the form of lubricating the mechanisim.
Am I wrong ? What do you guys think ?

Marko.

[belfastmark]

Hi.
Just to update the reason the barrel and housing was sticky and not returning
was due to spring return failure.
£20 for a new barrel etc from the scrap yard, switched the barrels
so I can use my existing key and job sorted.
Posted this incase anyone is experiencing similar issues.