Tube smell?

Some 5687 tubes I just installed have a mild but definite
burning-rubber odor. It's not extreme, but it is there
if you sniff around them (and I can also detect it around
the room). Has anyone ever had this? Could it be something
oxidizing because they are newly installed?

It's a bit hard to tell, but it seems to be all 4 of them,
not just one.

The tubes work fine, but look brighter than
my old cheaper 5687s. They sound absolutely great,
nice and smooth and mellow.

It's not the amp, as the old tubes don't smell.

Thanks for any help.
Hey Atmasphere--Thanks!! I rubbed them with
a damp tissue and it actually worked! There is
now only the slightest aroma very close up.
It may have been just one of the four, but
I cleaned them all. I really appreciate your help.
Now my wife won't complain.
tube smell??? I LOVE IT!!!!
Me too.

The Baby amp from Sophia has a really cool smell. I have had 3-4 different ones over the years and they all smell the same.

Charm of tubes...
My tubes don't smell, something's wrong...wahhhhhhh!
I just put a fresh quad of Shuguang KT88-98 tubes in my VAC amps and for the first 8 hours or so, they had a distinctive odor to them. The odor gradually faded away.