Need advice on how to unjam 2 plugs

[OM2]

I have 2 sinks plugs
Both are jammed

They've been pushed down - but now there seems to be no way of popping them back up
In another post here I was told that you simply press again and they should popup!

See the pictures below:

One of the plugs seems to have a few bits of hair in - but th eother one is clean

QUESTION: if I have no choice but to buy new plugs, are they standard sizes?

Thanks


OM

 

[foxhole]

Try a good dose of wd40, or they may simply have worn out, [should not have rust on them.]

 

[OM2]

thanks
i'll give wd40 a go

if not working - are these all of a standard size?
thanks