Nokia Applications :: Way To Uninstall Hidden Themes

i had downloaded several apps and themes from ovi store. i tried all possible menas to locate them. also ion Settings>App Settings>Installed apps. but they are nowhere to be seen and some apps to which were compatible with anna and not with belle also when i connected my phone in mass storage mode. i found sys/bin folder and others containing old apps and some information which are not compatible with belle. so is it safe to remove them because they are just occupying space.