Normally, you could use 'LIKE' in the query to find a string. For example to find anything with 'W' you'd use this in the criteria of the query's field:
Like "*W*"
However, it won't work for the hash, as it's used by access to delimit dates.
Instead, add a calculated field to the query:
HasHash: InStr(1,[myField],"#")
and in the criteria enter:
<>0
Max Hugen
Australia