Some scary advice in this thread, and some good, you have to know what the material is (Not the manufacturer, there are 100's of FR clothing manufactures but just a few manufactures of the FR fabrics). You need to go to the source. I have about everything on file so if you post what fabric you have I can help out.
Also be aware they added care of FR clothing to the 2012 70E
(13) Care and Maintenance of Arc-rated Clothing and Arc-rated Arc Flash Suits.
(a) Inspection. Arc-rated apparel shall be inspected before each use. Work clothing or arc flash suits that are contaminated, or damaged to the extent their protective qualities are impaired, shall not be used. Protective items that become contaminated with grease, oil, or flammable liquids or combustible materials shall not be used.
(b) Manufacturer?s Instructions. The garment manufacturer?s instructions for care and maintenance of arc-rated apparel shall be followed.
(c) Storage. Arc-rated apparel shall be stored in a manner that prevents physical damage; damage from moisture, dust, or other deteriorating agents; or contamination from
flammable or combustible materials.
(d) Cleaning, Repairing, and Affixing Items. When arc-rated clothing is cleaned, manufacturer?s instructions shall be followed to avoid loss of protection. When arcrated clothing is repaired, the same arc-rated materials used to manufacture the arc-rated clothing shall be used to provide repairs. When trim, name tags, and/or logos are affixed to arc-rated clothing, guidance in ASTM F 1506, Standard Performance Specification for Textile Material for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards, shall be followed [see Table 130.8(C)(14)].