I changed mine a while back, first I washed the engine with Simple Green, using common sense around electrical stuff. Then re-washed the fuel container with a rag and Dawn.
Next drain the canister for about 10 seconds, loosen lid to break seal and finish draining canister. This will usually result in diesel being dripped somewhere. Now unscrew lid with hand, remove and replace filter inside canister. Remove old O-ring from lid, install new O-ring and re-install canister lid.
Can you do this with a dirty lid? and not leave prints, Nope......
Jim
Mine @16K miles. The black is not dirt, it is the result of the fuel getting hot and cooking the material Tar is made out of out of the fuel. Normal condition.
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2012 Ram Laramie 3500 DRW 4x4 3.73 Tow Max Pkg B&W Companion 60 gal RDS aux fuel tank. 2014 Montana 3150RL, 2 A/C's, Leather, 6 Point Jacks, Splendede WD2100XC, Mor/ryde X-Factor, Duravis 250 tires with TST 507RV monitors. 2 x Honda EU2000's