If your Olin MP4 player (OM206) shows that the internal memory is full, you can free up space by deleting unwanted files or transferring them to a computer. To do this, connect the player to your computer via USB, access the file directory, and remove any unnecessary files. You can also check the user manual for specific instructions on managing storage or resetting the device if needed. If you require the manual, it may be available online through the manufacturer's website or other manual repositories.