Good Ol' Fiberglass To the Editor: I read with great interest about the new wet cellulose insulation and the so-called great results ("Contractors' Tips for Spray-Cellulose," JLC, 8/89). Many other items are long-gone, such as cellulose with added insecticide and ureaformaldehyde (UF) foam, with its related outgassing and high shrinkage. About ten years ago, cellulose was treated with aluminum sulfate, causing high corrosion. What next? Fiberglass, though it may not be glamorous, is still there in 78 percent of old and new construction. Richard Hammond Keene, N.H. From Ireland to America To the Editor: Being one of your fond subscribers for some years I hope you can help me or point me in the right direction. I have a nephew and his friend