I have a 20 year old Ritchie flush mount binnacle compass that has, in the last couple of months, developed a bubble which is growing. I understand that this means it has developed a leak, possibly from remaining on the boat through the winter and being subjected to significant heating/cooling cycles. Does anyone have experience opening up the compass themselves and refilling it (mineral spirits?), and resealing? Does it need to be done by an "authorized service tech?" If so, what should I expect to spend? Thanks for your response.