Hello,
You seem new to the board, but anyway, I guess a vast majority of players are shooting their spares with mostly plastic/polyester bowling balls (C300 White Dot, Brunswick Target Zone, Ebonite Maxim, etc...).
There is discussion of how you can learn to shoot spares with a plastic ball somwhere here (do a search), and I suggested using the Parallel Spare Shooting System.
Also, finally, if you do decide to go on and get a plastic ball for your spares, don't be discouraged if you do not get immediate success. There is a learning curve for this type of Spare Shooting System.
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-Jeremy Vitug
It is YOU who decides what happens on the lane.