Are EE Top-Up cards still valid?

[achalk]

I am a UK expat. I have accumulated three EE Top-Up cards in my 'phone' draw. 

Are these obsolete (I always top-up for trips online)? They appear to be an obsolete technology.

Do they have any monetary or minutes value stored up in them? If  so,, how do I find out what it is?

If it sounds like I don't completely understand the concept of Top-Up cards that is correct.

Thanks!

[XRaySpeX]

They have no monetary or minutes value stored up in them. They are associated with a particular mobile no.

Otherwise just use Fast Top-up online to pay by UK bank card. You don't need to login or register anything. All you need is your mobile no. & it doesn't remember your card details.

[achalk]

Thanks. As an expat, I don't have a UK Bank Card but presumably can get the same terms with Visa/Mastercard?

Thanks!