Possul

You should not use your best friends as witnesses as they may be considered prejudiced and may possibly be considered posul as witnesses.

Perhaps you should avoid this Chabad house--by your standards their sefer torah is probably possul, since it's only been checked and fixed by a chalav stam drinker.

I’ve seen many taleisim before, dose of Chayim and Yossel. But as for your tallis, I must say, dis iz definitely possul. I could vork on your tallis some more, but it really doesn’t pay. If I vere you, I vould buy a new tallis, and throw dis old von avay.