Further to LanX's reply: In addition to using  { } curlies to limit/select scope, one can fully qualify package names:

c:\@Work\Perl\monks>perl -wMstrict -le
"our $VAR = 5.0;
 sub printit { print 'Package ', __PACKAGE__, qq{ VAR=$VAR}; }
 ;;
 package A;
 our $VAR = 2.0;
 sub printit { print 'Package ', __PACKAGE__, qq{ VAR=$VAR}; }
 ;;
 package main;
 ;;
 A::printit;
 printit;
 main::printit;
 print 'Package ', __PACKAGE__, qq{ unqualified VAR=$VAR};
 print 'Package ', __PACKAGE__, qq{ fully qualified VAR=$main::VAR};
"
Package A VAR=2
Package main VAR=5
Package main VAR=5
Package main unqualified VAR=2
Package main fully qualified VAR=5
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