From UroWiki
Snalt on an uromastyx ocellata's nose
'Snalt' (a Portmanteau of
snot and
salt) is the white substance that forms around an uromastyx' nostrils at any given time. It is formed by the excretion of excess salts, such as sodium and potassium, from the lizard's foodstuff. The buildup of snalt is a possible indicator that you need to review the sodium and potassium ratios of your lizard's
diet. Snalt usually falls off naturally, or is rubbed off against the substrate or rocks; this is perfectly normal and is generally not an issue for concern.
