When I went to the vet my chams mouth didn't have any mucus in it but believe me he had URI. My vet didn't want to do any culture or blood test because he said the throat was clear so he said "if I wanted to", he can give me Baytril.
I told him I'd use it only if I see the mucus comes back, good thing I took it cuz I did see the saliva again after 2-3 days.
Sometimes I see it, sometimes I don't. It's better to take preventative measures than go to the vet when the cham is really sick and won't eat.
Usually, by the time you see something is wrong, it's too late. My cham was still acting normal & eating and drinking when I took him to the vet.
But because I see him everyday, I know something is wrong. His colors were off.
My other chams do not open their mouths unless it's too hot and even then I don't see them drooling or have excess saliva in their mouths let alone see bubbles coming out of them. Their mouths are usually closed so when I saw my cham in this situation, I didn't take a chance and just had him checked. Plus, since I was there I had the vet do a fecal & they said he had worms (roundworms I believe) and this was fairly common.
PS
Believe me, I hated that 1 1/2 hr drive stuck in traffic. It took me 4 1/2 hrs before I got home.
And I went straight to the vet after coming home from work. And my works starts at 5:45 am ..ugghhhh
Plus, I was thinking of it this way.. Do I want to lose $350 or do I want to spend $100 for the vet?