I use an eye dropper to drip vinegar on the felts. It's all natural and way safer than wallpaper remover, and won't damage the paint. It’s considerably cheaper too. It takes about 15 minutes to do, then let it sit for about half an hour or so. When you come back, most of the felts will literally fall off when you touch them. Those that don't get another few drops of vinegar until they too fall off.
Of course, you have to wait until they dry completely before gluing on the new felts, but this method should take your time down from 5-6 hours to under one hour of labor for removal.
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Benjamin Sanchez, RPT
Piano Technician / Artisan
(256) 947-9999
www.professional-piano-services.com------------------------------