This mantra is frequently referred to as Śunyata Mantra, although the words themselves focus on śuddhā or purity, so I have called it the Purity Mantra to distinguish it from the mantra which focuses on the word Śunyata.
tibetan - Uchen
oṃ sva bhā va śu ddhāḥ sa rva dha rmāḥ sva bhā va śu ddho 'haṃ
oṃ svabhāva śuddhāḥ sarvadharmāḥ svabhāva śuddho 'haṃ
Translates literally as: "oṃ (by) self-nature pure (are) all dharmas; by self-nature pure (am) I."
Which I would render...
Oṃ. All Dharmas in their own-being are pure; in my own-being I too am pure!