u/tangledupinblue22

Hi everyone! Not sure if this belongs here so please let me know if not.

I was cleaning and found this weird dirt looking stuff on an envelope. It has been on the ground (carpet) and the carpet also has weird spots like dirt, but it doesn’t wipe off like dirt.

Any ideas? Could it be mold? I have a newborn and child with allergies so definitely want to do a deeper clean if it is!