print "$_ : ",  do{ 
    ($_) = m[ \( ( [^)]+ ) \) ]x; 
    tr[,][]d; 
    $_ 
} for map "($_)", qw[ 1,234 1,234,567 1,234,567,890 ];;

(1,234) :  1234
(1,234,567) :  1234567
(1,234,567,890) :  1234567890