Alice, I would use the toothpaste, as advised! There is machine oil on the nib, to prevent rusting. You have to get that off in order to get the nib to accept ink. I have an old toothbrush & I put some toothpaste on it and scrub away. THEN, you want to rinse all of the toothpaste off and dry the nib. Be sure to not handle the end of the nib that accepts ink. - Your fingers will have oils on them that may repel ink & you'd have to repeat the process! I use a small pair of pliers that I got in a craft store in the jewelry-making section to pick up the nib & insert it into the nib holder. That way, I don't touch the nib after cleaning it with the toothpaste.
Post back if this doesn't work!