No offense, but are you saying that CHRISTIANS cannot take communion in a "Catholic" (Christian) church?
Even many Catholics should not take Communion in the Catholic Church. Unless you have confessed your sins and been absolved of them leading you into a State of Grace, it is a MORTAL SIN to take and eat of the Flesh of Our Lord. If you are a validly baptized Christian and you present yourself to the Lord in the Sacrament of Penance with true sorrow for your sins and abjure the errors of your apostasy, then you too may accept the actual Body and Blood of Our Lord. I pray that you do so.
This is one area where I think Catholics need to re-assess their dogma.
Since the Dogma is a direct COMMAND from God Himself, that simply cannot happen.
You do realize that you don't even know half the sins you commit in a day.
Same with me and every other Christian. We can't possibly be "absolved" of them all by talking to a priest prior to Communion.
All Scripture requires is us to discern the Lord's body rightly, which means to take the occassion damn seriously.
The man who kept the memento wafer obviously did not, and I feel he probably is drinking judgment upon himself for his loose treatment of the sacrament.
However, all that must be done is for us to discern our hearts and the Lord's body, what he did on that Cross.
Nobody can be perfect when taking part.