I've had more than one avian vet tell me not to use topical pain relievers, like lidocaine or any products that numb or end in caine. Apparently it can be toxic to birds at some level.Plain water, deal. We have actually an unused real pool I could put her in. She won't be able to come out alone, (at least, not easily) the water level is so low, 6 ft down from the edges. Something my GF just mentioned is, nail techs rub half a lemon first, then put vaseline to soften up nails before working on those. Could this work to loosen the core up in this case? Another thing I have is a CVS "Pain Relieving Antiseptic Spray" with 2.5% Lidocaine HCl that might work (or not?) as a partial analgesic for the pain of core removal.