How best to eliminate LP warps


I own about 2500 LPs, and I like to think they're flat.  Furthermore, I espoused the view that warped LPs ought to be discarded.  But lately I have found 2 or 3 of my LPs that do have warps but sound too good and are too precious for the music recorded on them to throw away.  So I am in the market for ideas on how to remove warps.  I am aware that there was a device on the market that looked like a large waffle maker, to be used for warp removal.  I think Furutech made it, but I never see it advertised these days.  I am also aware of the DIY method of placing an LP between two glass plates and heating the ensemble.  The question there would be how hot and for how long?  Any suggestions are welcome, especially opinions on the efficacy of the Furutech.  Thanks.  Please no comments on vacuum hold down; I think it's a great idea but none of my five turntables has that feature.

lewm

There was a period where the Furutech DF-2 was no longer being shown on websites. I had the impression Orb had discontinued it and Furutech was no longer carrying it. Within the last year, I noticed a bunch of Furutech DF-2 units for sale- new. Price is higher now (big shock). 

It is pretty idiot proof, doesn't require rings and my experience with it--say 8 years- has been nothing but positive. I don't know if retailers have some wiggle room on margins here, but worth exploring. There is an even fancier Orb - the DF-3- which has additional features. One person I know who has an old Orb and the DF-3 found the latter to be less than optimal. I have not used it. 

It seems like half the new LPs I buy these days are shaped like soup saucers, so I broke down and bought an Orb a few weeks ago. I love this thing! Flattens dependably without affecting sound quality, unlike the old Vinyl Flat I used to use. Excellent product.