Anything you stuff into the can will eventually clog up with carbon and oil residue.
A cheap, but actually flammable material would be very coarse steel wool.
A not quite so cheap but definitely less flammable material would be a brass or stainless wire kitchen scrubber. It sort of looks like a steel wool pad, but alot looser woven and way more durable. 99 cent stores sell them at the best price. Still, that will not deaden the noise very well.
A typical muffler would have a set of baffles in the very center, inside a perforated tube, which is surrounded by a shock or sound absorbing matting such as fiberglass. The classic "cherry bomb" muffler as used on classic muscle cars is such a muffler, only no baffles. It has a straight through perforated tube with matting around it. I am sure you have heard them before.
Another type of muffler has a set of tuned length tubes or channels inside of it, sort of like a maze that the exhaust gasses must travel through. This is how a Borla or MagnaFlow muffler works. The tubes or channels are tuned in such a way as to cancel out the pulses of sound energy that the engine creates each time an exhaust valve opens.
All of these style mufflers have a decent or very good flow through them.
I am telling you all of this so you may understand better why you do not just want to try to suffocate the noise with a can full of material. That method creates too much back pressure. The engine has to overcome the resistance to flow that the exhaust gasses would encounter.
Try breathing through a blanket or a shirt wadded up. Your lungs must overcome the resistance to the air flow in much the same way the engine's exhaust would have to overcome a stuffed can muffler.
Can you say power loss?
Forced induction just by having a scoop or forward facing air filter with some kind of funnel on it will not have any benefit until you go 60 to 70 MPH. At that speed, it is just beginning to help out a teeny bit.
At vehicle speeds lower than that you would need a turbo charger or supercharger (AKA blower).
This has been covered before in a few threads, and the end result is typically "it would cost too much" or "the cheap Chinese engine cannot handle the extra power".
Don't get me wrong here. Do as you wish. An air scoop of some kind, done tastefully, would look pretty cool on a MB, but it would only be just that; a cool looking non-functioning thing.
Here's a link that explains mufflers better than I did: