@Kathy33
I've never recieved a cash tip and to be totally honest I'm not sure how I'd feel about it. I'm the home owner, I'm not hosting for a living, and (I think) we make it pretty clear we're hosts, not the cleaners or maids or housekeeping. All of our guests have left thank you notes and many have either brought us a little something (souvenier) from home or a gift to remember them by. We also give small gifts to guests or take them out to dinner or invite them to join us for a meal at home.
And Korea doesn't really have a tipping culture - only in special circumstances you might tip a server or cleaner or service provider when asking for something that is normally not provided to customers. It is assumed that employees are responsible for paying workers a fair living wage - they shouldn't have to be dependent on tips from paying customers.