Eustachian Tube Dysfunction: This condition is characterized by the inability of the Eustachian tube to open and close properly, leading to a feeling of fullness or clogged sensation in the ear. Given the patient's age and the absence of other symptoms such as fever, redness, or significant cerumen impaction, this diagnosis is plausible. The normal appearance of the tympanic membrane and the lack of significant cerumen also support this diagnosis.

Middle Ear Effusion: Although the tympanic membrane appears normal, a middle ear effusion could still be present, especially if it's a serous effusion. This condition can cause a feeling of fullness or clogged ear without necessarily altering the appearance of the tympanic membrane.
Cerumen (Earwax) Buildup: Despite the mention of only a tiny amount of cerumen, it's possible that the earwax is causing a partial blockage, especially if it's located in a critical area of the ear canal. Further examination or cleaning might be necessary to rule out this possibility.
Ear Canal Stenosis or Narrowing: This could be a contributing factor, especially in an elderly patient, where the ear canal might narrow due to various factors, including age-related changes or previous surgeries.

Acoustic Neuroma: Although rare, an acoustic neuroma (a type of tumor affecting the nerve connecting the inner ear to the brain) could present with unilateral ear fullness or a sensation of clogged ear without other significant symptoms. It's crucial to consider this diagnosis due to its potential impact on the patient's quality of life and the importance of early detection.
Nasopharyngeal Carcinoma: This is another critical diagnosis not to miss, as it can cause Eustachian tube obstruction leading to middle ear effusion and a sensation of ear fullness. Given the patient's age, this diagnosis, although less likely, should be considered.

Patulous Eustachian Tube: This condition involves the Eustachian tube staying open, which can lead to a sensation of fullness or hearing one's own breathing sounds. It's less common but could be considered if other diagnoses are ruled out.
Otosclerosis: A condition affecting the middle ear, leading to hearing loss and possibly a feeling of ear fullness. It's more commonly associated with hearing loss and might be less likely given the patient's presentation, but it remains a rare possibility.