Well, This is my take in this and I did some experiments on my SS Gladiator and MRF Grand Edition to test out. I have to say that I was very cautious considering the sheer quality of bats that was at stake.
A bit of science:
1. Trees suck up water along the direction of the grains and not perpendicular to them. This is the reason why the toe of a bat is the most vulnerable in addition to the fact that it is exposed more to the factors such as dampness of the ground. It is also subject to most of the abuse (apart from the middle of the bat that is). That is not to say that if you have a splash in the middle of your bat, you should not be worried. Timber being a porous material, that splash may prove costly and spills should be wiped off immediately. I had a BAS Vampire Grade 2 Willow bat, with which I played on damp ground and trust me, it had some serious swelling near the toe. That bat was later machine rolled and turned into a beautiful tennis ball bat.
2. Steam - We all know that water is harmful for a bat. But then, steam is a different proposition. The reason for the same is how much of steam? 10 grams of water when converted to 10 grams of steam, is actually, a hell of a lot of steam. If I expose my bat to a jet of steam from a steam cleaner for a minute, that is equivalent of 10 grams of water at the best (approx). Out of that 10 grams of steam, most of it is going to fly off. At the best a gram of it is what would condensate on the bat. If one is careful about wiping it off immediately, a good amount of it gets into the towel, leaving about 0.1 of a gram of water. That is a rough, back of a tissue paper calculation. Having said that, steam is hot and it is the heat that is damaging. Prolonged exposure would cause damage to the wood. So, short bursts of steam of up to 10 sec and up to 5 times with 5 minutes break in between, shouldn't be a concern.
Finally, it is about time to put theory to practice. As I said, what is at stakes are two beautiful blades that have been bowlers envy, but also have enough dings of various sizes on the face, on the back and on the edges. Having stripped the extratec and edge tapes, I set out with a towel, linseed oil and steamer with me and did exactly 5 bursts of steam, each not more than 10 sec on each ding on each bat and this is what I have to report -
1. Smoothened out big dings - No, the size of it remained the same, but the edges seemed to have softened out.
2. Small dings of 1 to 3 mm have disappeared - But really, do you guys really worry about dents so small?
3. Dents (sorry Craters) on the bat face remained as they were.
4. The steam seemed to have cleared up the linseed oil coating. So, I have oiled the bats again.
Quite frankly, I have not seen any significant differences between the before and after scenarios here. The bats were oiled, dried and replacement extratec on them. Didn't feel a thing in the nets - the bats were exactly the same. If anything, a few minor, inconsequential dents have disappeared. That is all there is to it.
Is it worth the pain? No. Shall I do it again? Never.