Welcome to the forum :-)
What I try:
- use ultrasonic cleaner to dislocate some of the dirt inside
- soak in penetrating oil to try breaking crust inside apart. clean afterwards!
- you can also try soaking in vinegar/baking soda or coca-cola or other solutions. sometimes it helps.
- use a pair of pliers, one on each piece of the cartridge. put rubber underneath for grip.
So far I managed to open (I think) all uncleaned cartridges that came with models I purchased by using above methods. Pliers are last resort. Sometimes all the cart needed was to break the initial inertia, and after just a tiny twist using pliers it opened further without issues (rubber gloves did not work). Sometimes more force was required, often leaving scratches where plier teeth gripped the cart. This can be polished to some degree, and should not cause problems during operation.
If you have Marushin cartridges with steel detonator pin and/or cartridge bottom, keep in mind it will rust in no time if you soak it in water.
Thu Dec 08, 2011 8:57 am
Thankyou gentlmen 
