T5inthe12

hi all i'm new here and joined to find some info on cobalt. my parents own an older catalina model cs-3. we are in a remote location in the so. cal. desert. they take good care of it and keep it covered. in the last year or so hairline cracks have developed that turn black. no matter how many times the black is wiped off it reappears. it has an oily feel to it. thinking it was algae, i asked a guy at the pool store. he stated that cobalt was used in the manufacturing process in those days and to wipe it off and use clear nail polish to make it stop. doesn't work well. my ouestions for you more experienced here are: is it in fact cobalt, if so can it be stopped or covered, is it unhealthy, will it ever stop oozing out of the cracks. appearence is not as important as function so if it isn't harmful it might not be a problem after all. i was surprised to find this a rare thing while searching the forums. any info wld be appreciated. th anx