from light by wrapping with aluminum foil. Autoxidation of the iodide and rehydration may be retarded by storing the work in a desiccator in the dark. Safety and Waste Disposal Information Caution: Cobalt(I1) is toxic a n d must not be ingested. Students must not lick brushes containing the cobalt pigments. Hands must be washed afterpainting. Stock solutions (except for NaI) are stable and can be kept indefinitely. Prepare only enough pigment for painting. Single small ~ a i n t i n e smav be out in the trash (onlv " m i ~ o m o l equktities-of codalt are involved). For larger amounts of cobalt(II), leach the pigments from the paintings, precipitate cobalt(I1) hydroxide (which is autoxidized to Co(OH)O(aa)) with 0.1 M NaOH, and filter. The solid may be taken t o a landfill (12) or, preferably, recycled to recovercobalffI1)(13).ARer neutralization, the filtrate may he flushed down the drain with much water. Acknowledgment This paper is based on work supported by the National Science Foundation under Grant Number MDR-87-51183. Literature Cited 1. Sone. K: Fukuda, Y. Inorg.nic Tharmoehmmlsm;Springer Verlsg Berlin, 1987. 2. Shakhaahiri, B. Z. Chemicol&mns*rotions:A Hondbmk forT
