Hou keeper was honest with $ i left in room. Advice

So I’ve lost money in the past accidentally as many housekeepers in hotels take things aren’t honest even in nice hotels and I stay on hotels a lot for work anyways a few days ago I stuck a $20 bill under the bed and accidentally fogot I left it there so I was happy to find it laying on the desk and that they saw it left it and were honest. So my question for you is should I tip them some or all of it to thank them for their honesty and what would you do? It means a lot cause no one is been honest of I left cash accidentally on a room before I really try not to.