Try a soak in lukewarm bioviolent washing liquid and after that, swirling some dry rice in it to remove the loosened gunk.
It's a far safer first bet than trying anything of a mechanical nature!
It's a very elegant shape - I'm afraid though that (IMNSHO
) this colour combination, when not related to something from the '60s onwards, is just... eeeeeeeeek!
Perhaps "stunning" would be a more diplomatic word to use - but I would be meaning
"eeeeeeeeek" so it would be dishonest.
It's an absolute treasure of a find. Well done!