dust

This Fundamental Mind can be compared to a mirror, and whether covered with dust or not, a mirror is a mirror. It remains unchanged no matter how long it is dirtied and covered with dust, and once the dust is removed, it gleams as brilliantly as ever.

Even golddust is only dust to a mirror and an obstruction to its function. In the same way, words of the sages are but dust on our Fundamental Mind and they merely darken it.

-Zen Master Song Cheol

The ignorance and dust of desires are enlightenment and the sufferings of birth and death are nirvana.

-the Maka Shikan

I suppose it depends on what teaching suits you at this moment...