Hi. I have been smoking pipes for about a year and a half. I use each pipe about once a week. I clean my pipes with cleaners after each use, and after .4-5 uses I use a pipe sweetener solution in the stem and shank. I have not done any other maintenance. For the last month, i have been having trouble burning the last 1/3 of my bowls. I am relighting 5-6 times. I have not changed my tobacco, drying time, or packing method. Could I be missing something in pipe maintenance? I have smoked about 60-80 bowls in each pipe. Do I need to ream out the chambers or something? Thanks in advance for your replies.