Searching for specyfic various unusual signs

I need to find all files with such signs in FILENAME, with one expression in FreeCommadner:

Æ, ã, ā, À, å, è, ê, ī, ñ, û, ŵI failed at in FC, so I went to Mp3tag to the Filter Box. And failed again; either because I just don't comprehend regular expressions or because those unusual signs require some special treatment

Here are my failed regexp attempts [with the first and last character]

$regexp([Æŵ])
$regexp([Æ|ŵ])
$regexp([Æ*|ŵ*])and failed filtering expressions
(FILENAME MATCHES Æ) OR (FILENAME MATCHES ŵ)
(_FILENAME MATCHES Æ) OR (_FILENAME MATCHES ŵ)
(FILENAME MATCHES "Æ") OR (FILENAME MATCHES "ŵ")
(_FILENAME MATCHES "Æ") OR (_FILENAME MATCHES "ŵ")

So can anybody provide me with the solution to my headache?

See Mp3tag help file, section Filter, at end of the page, do apply the right syntax.

DD.20170926.1652.CEST

As DetlevD said it is in help but since I had already composed a reply here is some fast-acting headache relief. First, you need only the HAS operator to filter on one character anywhere in a file name:

%_filename% HAS Æ

When specifying the field for a filter, it's best to use the provided list by clicking the right arrow at the far right of the filter pane and selecting the item. Mp3tag will then automatically insert the name in the correct format.

To find any character in your list anywhere in the file name:

%_filename% MATCHES "(Æ|ã|ā|À|å|è|ê|ī|ñ|û|ŵ)"

To find any character in your list at the start of the file name:

%_filename% MATCHES "^(Æ|ã|ā|À|å|è|ê|ī|ñ|û|ŵ)"

To find any character in your list at the end of the file name:

%_filename% MATCHES "(Æ|ã|ā|À|å|è|ê|ī|ñ|û|ŵ)$"

One caveat: the above examples use UTF-8. If you are searching on other character sets, you may need to use the appropriate version of the special characters.

I stumbled over this thread on character classes:
/t/16126/1

So a filter with
title MATCHES [[=A=]]
should return all titles that contain a character that looks like an A with all its variations.

Yes, this works; thank you

Thanks but that is not the issue here. I only need to find signs that make the MP3val choke. And those signs listed by me are such ones known to me; because I have at least one filename with at least one of those signs in them: https://sourceforge.net/p/mp3val/bugs/24/

[I need to remove such ill-characters, by removing files that have them, and only then load safe files to MP3val for evaluation]