By "Steel Bedding" I'm assuming that you are going to use something like Devcon Plastic Steel.
The principle behind a "release agent" is merely to prevent the epoxy base of he bedding agent to bond to both the stock and action. Almost any oil or wax based substance will work. The reason some people use Pam is it's "quick and dirty". Spray on and plop the action in the "goo" that's already spread in the stock.
You can also use the specific "parting agents" that are commonly used in the fiberglass molding industry which is usually a spray on Polyvinyl Acetate (PVA) material that forms a barrier between mold and the epoxy.
For a small job like bedding a rifle action the most commonly used product among the DIY crowd (and a lot of gunsmiths too) is just plain Kiwi Shoe Polish (Neutral so it doesn't stain wood stocks). Clean the action of all oil, grease, and dirt then apply a coat of the Kiwi to not just the area you will be bedding but anywhere the epoxy might spread or be dribbled and you don't want it to stick. I wax at least 1/2"-3/4" above the "part line" where the action leaves the stock just to make sure.
It's not just a matter of smearing the wax on and then expecting a great looking finished job. Take some time. Apply the wax, let dry, then polish it down to a smooth surface. If you don't, when you part the action from the stock you'll have all the excess wax left on the action and a crappy looking finish on the cured epoxy.
Add some wax to the threads of the action screws and run them in/out of the threaded holes a couple times to make sure the threads in the action are waxed too.
It's important to make sure that the action isn't rotated in the stock when bedding. I found that adding an o-ring that fits over the action screw and then fits inside the "pillar", with the OD of the ring just touching the ID of the "pillar" not only makes sure that the action is not rotated off center (if it's a round bottom Remington) and keeps the epoxy from flowing into the pillars. You can also wrap the screws with electrical tape, again so they are centered in the pillar holes. Just make sure the tape is wrapped evenly and the end of the tape on the last wrap matches where the end of the first layer lies.
You also want to make sure that no epoxy makes it's way into the bolt locking lug area. I do this by installing the bottom metal then insert the screws with 0-rings before laying down the epoxy. The 0-rings hold the screws and bottom metal (Leave the magazine box, spring, and follower off the bottom metal for this part) Spread the putty then carefully set the action on the screws. Start the front action screw first as this is the most critical one for keeping the epoxy out of.
Once you have the screws started, just tighten until they're finger tight, no more. Secure the action to the stock with surgical tubing, wrap with bungee cord, or if you have one of those Physical Therapy exercise elastic bands, use it. You want the action to be held in place with no internal stress that can be induced if you tighten the action screws.
If the stock is sloppy, you might want to put an O-Ring around the barrel, right at the tip of the forend that spaces the barrel at the front the desired amount. Then let the action sit on the stock at the tang (rear). If the pillars (or action block) is in good shape then just use them (it) to locate the action in the epoxy while it cures.
Now back to the original question------- Use Kiwi Shoe Polish
I've done more than a dozen bedding jobs and still haven't used up my original can of shoe polish.