[yusuf]

I use 3M micro-fiber and never had any issues.

[mikeSF]

I switched to dish detergent and hot water for all my ND filters and no more streaks. They get perfectly clean and I've not noted any ill effects to the coatings.

[Miguel]

Your Hoya Pro One digital is considered one of the better filters made. Not quite B&W but exponentially better than Tiffen. I had a long discussion and demo with the most highly respected lens repair craftsman in Seattle. The subject was filters. The difference between filters are the longevity of their coatings. Cheap filters, like Tiffen, have coatings that wear or flake off sooner than better filters like the better levels of Hoya.
BTW, he sells all the brands, and for the record, the profit for a better brand may not be any better than a cheaper one. Anyway his filter prices were competitive all the way around.
Perhaps the OP needs to use more appropriate cleaning tools.

M

[Lokusart]

Your Hoya Pro One digital is considered one of the better filters made. Not quite B&W but exponentially better than Tiffen. I had a long discussion and demo with the most highly respected lens repair craftsman in Seattle. The subject was filters. The difference between filters are the longevity of their coatings. Cheap filters, like Tiffen, have coatings that wear or flake off sooner than better filters like the better levels of Hoya.
BTW, he sells all the brands, and for the record, the profit for a better brand may not be any better than a cheaper one. Anyway his filter prices were competitive all the way around.
Perhaps the OP needs to use more appropriate cleaning tools.

M

I quite like the flare handling of the Hoya, I think it does a pretty nice job. I have to try a lenspen to see if it's practical

[mikeSF]

Your Hoya Pro One digital is considered one of the better filters made. Not quite B&W but exponentially better than Tiffen. I had a long discussion and demo with the most highly respected lens repair craftsman in Seattle. The subject was filters. The difference between filters are the longevity of their coatings. Cheap filters, like Tiffen, have coatings that wear or flake off sooner than better filters like the better levels of Hoya.
BTW, he sells all the brands, and for the record, the profit for a better brand may not be any better than a cheaper one. Anyway his filter prices were competitive all the way around.
Perhaps the OP needs to use more appropriate cleaning tools.

M

no, I know what the OP is talking about. My Hoya 9-stop NDX400's all seem to show smears on the coatings that take some extra work to remove. ive concluded it to be a property of the coating but obviously I am no expert. My B+W, Tiffen, and Marumi's do not tend to smear by comparison.

[Lokusart]

I forgot to add that I wear glasses since I was 7 years old, so don't tell me I don't know how to clean a piece of glass



EDIT: A follow up that may help people who encounter the same problem in the future. Hoya filters really need special care for cleaning, they are great value for money, but when it is time to clean them it can be kind of an hassle. I tried the lenspen (I'm not receiving a commission ...saddly) and it is by far the more efficient way I tried, so I'm keeping the Hoya and the Lenspen.