You should not use bleach. Bleach is ineffective on porous materials like blankets, as it only removes surface discoloration without addressing the root fungus. More importantly, agitating the mold by cleaning it yourself can release a large number of spores into the air, potentially worsening your children’s respiratory symptoms.

For the blankets, the safest course is to discard them. Mold roots penetrate deep into fabrics, making complete removal nearly impossible with home methods. For the closet itself, this requires a specialist. The persistent dampness indicates a moisture problem that must be identified and resolved; otherwise, the mold will return. A professional inspection will use moisture meters to find the source—whether it’s condensation, a hidden leak, or rising damp—and recommend the correct remediation protocol. This is not a scam when done correctly; the evidence is in the before-and-after lab reports that a reputable company should provide, showing spore count reduction. Given the health symptoms and the extent of growth you’ve found, arranging an assessment is the recommended next step.