A serviceable muffler (20) has an end plate (34) releasably clamped (36) to an open end (30) of a muffler body (26) and permitting access to an internal catalytic or filter element (28) for removal and replacement. An apertured flange (44) has an outer border with flared rounded portion (46) complemental to flared rounded portions (40 and 42) of each of the end plate (34) and the open end (30) of the body (26), and having an inner border defined by an aperture (48) through which the element (28) is removed and replaced. Servicing and manufacturing methods are provided.