304 vs 316 Stainless Steel for Outdoor Sculpture
The grade decision costs little at the quotation stage and a great deal once a piece starts pitting. Here is how to make it properly.

Very little is needed, but the wrong product used once can undo a finish that took days to achieve.
Rinse with clean water, wash with a neutral pH detergent where there are fingerprints or traffic film, then dry with a soft microfibre cloth. Drying matters more than washing, because water left to evaporate leaves mineral spotting that is more visible than the dirt was.
Steel wool, abrasive pads, scouring powders and anything chloride based. Steel wool leaves iron particles embedded in the surface which then rust in place and look exactly like the stainless steel has failed. Bleach and chloride cleaners attack the passive layer directly.
A mirror surface within reach of the public will carry fingerprints for as long as it is open. That is inherent to the finish. Where daily wiping is not realistic, a brushed or hammered finish achieves a similar presence and hides handling far better.
Grinding dust from carbon steel, sparks from nearby construction work and particles from a shared workshop tool all embed in the surface and rust there. On a new site, keep the piece covered until other trades have finished, and never let a tool used on mild steel touch it.
Rinse with fresh water on a regular cycle, and after storms or pool servicing. Salt and chlorine left to dry on the surface are what start pitting, and the routine that prevents it takes minutes.
Light scratching can be worked out by a specialist, but it means re-polishing an area and blending it into the surrounding surface, which is skilled work. Prevention through proper crating, careful handling and protection during installation is far cheaper.
Once a year, look at the base and drainage points rather than the surface. Blocked drainage, trapped leaf litter and standing water at the base cause more long term trouble than anything that happens to the polish.

Stainless Steel Mirror Creative Leisure Seat Design A
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Large Stainless Steel Love Shaped Sculpture
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Stainless Steel Mirror-Faced Large Sphere Design B
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Large Modern Outdoor Garden Decorative Metal Art Abstract Sphere
View detailsMost are fine if they are not abrasive and not chloride based. Test on a small area low down before using it across a whole piece.
Outdoors, rain does most of the work and a wash two or three times a year keeps it bright. In a lobby within reach of the public, daily wiping is what keeps a mirror finish looking as intended.

The grade decision costs little at the quotation stage and a great deal once a piece starts pitting. Here is how to make it properly.

A flawless mirror finish is decided during welding and grinding, long before anyone reaches for a polishing mop.

What weathering steel does over its first years outdoors, what it does to the paving underneath, and what to detail at design stage.
Send the position and the constraints and we will tell you which way the decision should go for your case rather than in general.