Sterling Paper Co. / The Schlicter Jute & Cordage Co.
Sterling Paper Converted Paper/Paperboard Product Manufacturers (established 1973) seems to have been the most recent tenants. Most signs have been painted over with some Philadelphia Mural Arts project, but the older lettering can still be seen beneath. Some inside info on the mural here.
City Atlas from as early as 1875 show the ornate buildings and clock tower facing Castor Avenue in place, titled “Aramingo Mills” but the entire area the building sits on labeled “THE SCHLICHTER JUTE & CORDAGE CO.” There are large signs at the rear (facing Butler) and sides (facing Coral) of the later buildings that read the same.
2155 Castor Avenue [map]