Hinged Maxxair vent covers will not swing open for cleaning

dougrainer wrote:
Use Liquid Wrench spray. Let penetrate for 24 hours. WD40 will not do the job. Doug

https://www.walmart.com/ip/LIQUID-WRENCH-Penetranting-Oil-11-oz-Aerosol-Can/16816124?wmlspartner=wlpa&selectedSellerId=0&wl13=1801&&adid=22222222227017003428&wl0=&wl1=g&wl2=c&wl3=42978149432&wl4=pla-81470068712&wl5=9027230&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=local&wl12=16816124&veh=sem&gclid=Cj0KCQiA9P__BRC0ARIsAEZ6irhRBSJhIXhLbbnd6Nzuvxe3P2WTq7_jOHTh2t58u87Qg_-UAidIGygaAkXLEALw_wcB

Tried that too,but when the wingnut is galled to the bolt and there is no way to hold the bolt from turning it will not break loose,believe me I tried it all. Went so far as cutting slot in top of bolt to hold with a screwdriver,still no luck...