Suede is different from other types of leather, and not just in texture; it is also cared for differently. You cannot use traditional leather stain-removal techniques to treat a stain, like oil, on suede. To clean an oil stain off a pair of suede boots you need to use very specific tools and instructions, otherwise you can damage the suede.
Spread out a section of old newspaper to protect the area you are working in. Place the oil-stained suede boot on the newspaper.
Pack talcum powder onto the oil stain on the boot. You can also use cornstarch. Leave the powder or cornstarch on the oil spot overnight. The powder will absorb the oil.
Brush the powder or cornstarch away from the oil spot with an old toothbrush. Bang the boot out a few times to loosen any embedded powder.
Hold a steam iron about 25 cm from where the stain was on your suede boot. Release a light steam mist over the formerly stained area.
Brush the area with a suede brush. This will help fluff the nap of the suede back up.