Save those squirt bottles
Give it a rinse with whatever you'll be holding in it, then purge the residue in the tube by giving it a few squirts.
I have three such squirt bottles at my workbench. One bottle has a 50-50 mix of mineral oil (baby oil, paraffin oil) and eucalyptus oil. I use it for lubricating sharpening stones, and for oiling my tools before putting them away (to prevent rust). I use mineral oil because I (naively?) believe that it's less harmful than WD-40 or motor oil; the eucalyptus oil smells nice and I think it maybe, possible, provides some additional cleansing/de-rusting action.
The second bottle has methyl spirits (basically, rubbing alcohol or denatured alcohol) for raising the grain, wetting end grain prior to planing, and also lubricating diamond stones (I just read [Christopher Schwarz] that if you use rubbing alcohol rather than water then they're less likely to rust).
And the third bottle has water, for wetting the surface of water-based sharpening surfaces (in my instance, wet/dry sandpaper stuck to flat pieces of tile).
Each bottle is a different shape and color, so I'm unlikely to grab the wrong one. And I also write the contents -- such as "WATER" -- in BIG letters with a permanent marker.