Brimstone's and cassettes

Definitely a spring day - I saw at least a dozen bright yellow brimstone butterflies on my lunchtime walk with the spaniel. This will be one of the earliest dates I've seen them. They were very flighty though and I didn't get to take any photographs of them. Instead we have the cassette tape problem - I've got loads of these in a box and have no idea what to do with them in the digital age.