EliSims
Elisims lets you delete walls pretty easily, my only gripe is the thumbnail for the walls are tiny. If you already have EliSims, and have a general idea of the color and sytle of the wallpaper you want to delete, the small thumbnails may not bother you. However, you can take an extra click to make the picture bigger. But with over 1000 walls, I could do without the extra click. The nice feature about this program, is that it doesn't make you start from the beginning of the list when you delete a file, like SimExplorer does.
Download
SimWallCat
You are probably familiar with the developer of SimWallCat - Paladin's Place. SimWallCat shows large pictures of the walls, making it very easy to tell if it is something you want to keep or not.
Download
HomeCrafter
HomeCrafter is a program developed by Maxis. It's primary purpose is to import jpg's and convert the file into wallpaper or a floor. However, you can view wall files already created. You can't delete wallpaper files in the program, but you could write down the file you want to delete, and then go into Windows Explorer and delete the unwanted walls there.
Download
