I just dewinterized RV and had trouble loosening water filter casing to put in a new filter. I was able to initially get it off and put back on, however, we recently had a cold spell and I wanted to take it off to remove any water and was unable to get it off. I am somewhat hesitant to use too much force in fear of causing damage to surrounding plumbing and fixtures. Questions? Any advise on how I can loosen the cover; and what I should do to resecure it after getting it off so this doesn't happen again. I was thinking about some type of lubricant such as plummets Greece or Vaseline. Thoughts? Thanks.