As it's been reported before that flexible parts appear to eat away the plastic that it's in contact with.
This is to inform everyone that this is indeed true for the blast effects.
I left one in my Omega for a while, and when a member at TFW2005 reminded me about soft plastic, I checked and found that it had indeed stuck together.
I twisted as gently as I could and it finally gave and came out, but leaving a small transfer of plastic on it.
So unless you are planning to never remove the blast effect from your display, I highly recommend not using them for long term.
For me, I've set them aside for picture sessions only, I'll never leave them in my figures.