The TUTORO Auto is manufactured from Thermoplastic mouldings, Stainless Steel, Brass and Nitrile.
TUTORO Chain Oil is safe with these materials but that doesn't mean to say all oils are safe with these materials, likewise its safe to use a mild detergent to clean the outside of the oiler body BUT its decidedly NOT SAFE to use any solvent base cleaner such as foam washes, degreasers etc. Solvents by their very nature are design to dissolve oil - most thermoplastics are oil based and as such are vulnerable to solvents.
See the photos below.
The Photo below shows a clear acrylic tube that has been attacked by an OIL - note the crazing pattern of cracks. (see plastics and lubricant compatibility)
This sequence shows the damage done by a Foam wash clear sprayed on and left to "soak" for awhile - as illustrated by the other photos in the sequence this can be avoided simply by placing a disposable plastic bag over the oiler if you want to carry on using a foam wash and don't want to damage the oiler.