[captainclock1988]

The only true dry electrolytic capacitors are solid type tantalum and niobium ones, but they are neither rated for the voltages used in tube radios, nor were commercially available at the time of production.

Now, to be a bit stern, here you have people with tons of experience, some of whom, in addition to being experts in this hobby, are also electronics professionals.
So when several people here tell you the same thing, it is ok to question the reason for it, but to argue is ...let's just say that it does not help you.

With Ron's permission, I will re-quote his friend, Rev. Lowell Mason:

"You don't have to agree with me. You have every right to be wrong if you want to be."

I'm not ignoring your advice, I'm just saying that in my opinion if the electrolytic caps are still working on these old radios I'd like to keep them in as long as they are working. 
When they start failing I will replace them, but in the meantime while they are still working I will keep using them.

And I'm not sure which Ron you're referring to here, but I don't think he would of actually of known Lowell Mason personally seeing as he passed away in 1872 and that would of been long before your friend Ron (whichever one you're referring to) would of been born, so there would of been no reason for getting his permission to use Lowell Mason's Quote, seeing as its Public Domain (as is all of his music).

I'm very familiar with Lowell Mason and his Music, I grew up in the Church and the church I go to we still sing those old Hymns and I have a hymnal collection consisting of over 60 Hymnals from various Denominations and Interdenominational Hymnals, my oldest hymnal being an old Methodist Hymnal dating to the 1830s (it was from the Methodist Church prior to their merger with the Evangelical United Brethen Church in the 1950s). 

I myself belong to a Church Denomination called the Church of the Brethren which is related to the Amish, Mennonites and the Quakers in that its one of the 4 Historic Peace Churches in America along with the rest of the aforementioned denominations. 

If you're at all Familiar with the church denominations like the Grace Brethren, Brethen in Christ (River Brethen), The Brethen Church (The Ashland Brethren), The Dunkard Brethren, The German Baptist Brethen,
The Ephrata Cloisters, in Ephrata, Pennsylvania, etc. those were all offshoots of the Church of the Brethen (which was originally called the German Baptist Brethren from the 1870s, up until 1908).

I hope this helps you out in seeing where I'm coming from in regards to my comments.