Slime in urine?

[DVirginiana]

If a frog had a problem with its urinary tract for a year bad enough for semi-solids to be coming out in the urine, I imagine there would be other noticeable symptoms.

Bits of shed skin will often accumulate around the hind legs and near the cloaca. That's probably what you were seeing. Keep a close eye out for any other symptoms just to be safe though.

[WakaWaka]

I find the same thing, I never worried about it because I assumed it was just him shedding as its easier to shed when his skin is wet. I'm not sure though.

[GrifTheGreat]

Mucus in the urine can be bad. Next time it happens collect the mucus onto a paper towel that is damp and stick it in a ziploc bag. Stick the sample in the fridge until you can get it to a vet for testing. Before 24 hours passes is best.If its a very small amount and white its usually not a bad thing, but if its pinkish or red you'll need to get your frog some meds.