Ah, modern tech (standards/protocols,python/odbc/LLM/etc) takes the fun out of restoring unknown data/data format from archived sources. aka mylar tape - regular expressions, awk, shell scripts,perl, hand-rolled statistical inference, trial and error to figure out what bit patterns/chunks generate most appropriate data.
Much better to filter/normalize data when entered or soon after completion of batch data entry when 'is this ok?' can be answered by those using data (vs. few decades later & no documentation/knowledge of intened purpose of data)