I would like to clean SM48 microphone but i cannot remove the grille. I've read from your site that SM58's grille can be removed with a few rocks, but does this means also for SM48, the grille is so filthy and "reshaped".
The grill should unscrew from the top of the handle. It could be corroded and/or stuck due to being dropped. You may need two strap wrenches to undo the grill: one to hold the handle; one to grip the grill. Once it is off, you can wash it and reshape it just like the SM58 grill.
The replacement grill is the RK248G.