If you bought yews around sreet value (250-300 each), you'll lose money pretty heavily because you only get about 90gp from each when you alch them. When I alch purely to lvl up, I use something I have an abundance of, usually some type of lower rune stone, like fires, waters, or airs. I get tons of airs when I kill chaos druids for herbs. Plus, you can put any number of runes in your inventory, so you're not constantly refilling inventory every 26 alchs . . . You only get 2gp per rune, but I don't alch for money . . .