The mucus can ONLY COME OUT via your Immune System that is working! So to guess that it is a cleanse would be a good guess. "IF" your diet is extremely perfect and you were in perfect health, then yes, your foods would not cause mucus.
Regardless of all the guesses, etc. the only cure is to stop eating and juice fast, nothing else works as well.
Your body can be filled with calcium/rock, but anyone who has flushed out a rock style stone 1 time and then changes their ways, I do not believe will see a stone again, because it takes time to create a stone and those who change their ways are stone free in the gallbladder. Those that change, flush their liver every day and no stone settles in ever again, the solution being plant fats.
I personally do not know of one person who has ever ate food correctly, so I expect every person to have a body filled with puss. Those with no puss would never waste their time on the internet talking about health. Healthy people never discuss health, it is a subject for us less than healthy people.