Clean the fan blades

Try using WD-40 or sewing machine oil on the bit that the blades are independent from the motor usually just a small opening that you can try to spray some lubricant in there which will reduce friction and noise by lubing up the bearing and decreasing wear if that helps you will then know what the underlying issues are and if you need further action

I picked up a Sunbeam Humidifier model 1118 for $7 (which was $7 too much) second hand. It wasn't until I got home that I noticed it was filthy-dirty inside...(dirtier than shown in the photos) the reservoir, the bottom tray, AND the fan chamber all needed major cleaning.

A quick Google search told me that the grill is "not removable", and the unit is "not user serviceable". Companies do this/say this for two reasons:

a) They want you to throw it away and buy a new one, landfills and plastic filling our oceans be darned
b) They want to protect themselves from lawsuits, should someone injure themselves servicing their product (or in this instance, cutting their fingers off on the fan blade).

Imagine if all of that design know-how was put into making the product serviceable, cleanable, and long-lasting, rather than ensuring it can't be opened or repaired by the average joe.

Me, I've opened and repaired enough gadgets to think differently.

You CAN remove the grille.
Carefully insert a series of flat-head screwdrivers between the grill and the body a few inches apart, wedging the grill edge away from the body.
There are slits in the body (see photos) that will allow you to get under the grill edge and pry it right out when enough of it has been detached from the anchoring groove.
But be gentle while you're doing it.
The Grille is plastic and flexible; it will bend, but if you use too much force you will damage either the grill or the body.

The photos also show how the grill is anchored to the body - via a groove in the grille edge.

You can put the grille back after cleaning the blades and fan chamber much the same way; pressing down, and if required: prying the side of the grill inwards with a flat head screwdriver.
Mine snapped right back into place with a bit of downward pressure.

you have to pop the cover off of the top if there are not screws holding the cover on then it should pop off with a screwdriver or you can use compressed air in a can that they sell in stores for cleaning computers

If you can easily get to motor I would unplug unit and check motor to see if it turns freely. If it does I would plug the unit back in and see if the humming noise is coming from motor. Ifyou decide that the motor is the source of the noise and you can do so safely spin the fan and see if it will try to run, If it does I would unplug unit and give fan motor and blades a thorough cleaning. Clean any hair,lint or dust from aaround motor shaft. A small motor like these does not take much to slow or stop them. Plug it back in and try it. If it stiil does not work I would replace the motor. Hope this helps. Thanks

TRY POURING IN SOME WHITE DISTILLED VINEGAR AND RUNNING IT. THE VINEGAR LOOSEN UP ANY SCALE AND JUNK. AFTER RUNNING UNIT FOR AWHILE, DRAIN OUT ANY REMAINING LIQUID AND ADD DISTILLED WATER OR FILTERED WATER. RUN UNIT AGAIN. THEN DRAIN OUT ANY LIQUID. NOW THE UNIT SHOULD WORK AS NORMAL. IN THE FUTURE, TRY USING DISTILLED WATER OR FILTERED WATER.

take the tank off and the fan unit housing. inside you'll see a circular filter that goes into the water sump. make sure it isn't falling apart and hitting the fan blades.

If someone put it togetherm you can take it apart.
See if the dicharge grill slides up and the bottom vcan be pulled out like a window screen. If so, ,other panels may also do so in order to access the internals, Unplug unit when in the water or around fan. Do not run unit without panels in place. Any fan cleaning use something like 409 spray and rinse off with a spray bottle also. Keep water out of all and any electrical. Rinse and leave no cleaner in humidifier to be mixed with misting. Good Luck

I have a Holmes cool-mist One-Touch Humidifier, and you can't reach the blades to clean them, and you can't take the console apart. I finally decided to use two spray bottles and clean and them rinse the Humidifer while holding the console upside down and over a sink. The one bottle you could fill with any mild cleaner plus a lot of water to dilute the cleaner. Maybe dishwashing liquid (not the dishwasher stuff), or a little bit of ammonia, or rubbing alcohol, or vinegar. Spray that on the blades while the machine is upside down, and a lot of sooty dirt drips out. Then rinse with another spray bottle full of plain water. Leave the console upside down on a towel to drip-dry. This is also how you can clean silk flowers that collect dust.

the best way to clean the fan blades is to take like a paint brush or some type of brush and clean it that way. there isn't a way to take that apart. if you try to it can be difficult to put back together. if you have any other questions please let me know

if the water panel needs to be replaced , this can happen. instead of going through the panel , water will run on the outside of the panel and drip through the seems on the humidifier cover. make sure the plastic hose that goes into the water panel is inserted into the water panel.